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https://github.com/butuzov/leetcode.go
Hands-On Practice
https://github.com/butuzov/leetcode.go
algorithm-challenges algorithms datastructures golang leetcode
Last synced: 23 days ago
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Hands-On Practice
- Host: GitHub
- URL: https://github.com/butuzov/leetcode.go
- Owner: butuzov
- Created: 2018-08-05T07:45:54.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2021-11-14T18:18:42.000Z (almost 3 years ago)
- Last Synced: 2023-02-26T02:46:43.817Z (over 1 year ago)
- Topics: algorithm-challenges, algorithms, datastructures, golang, leetcode
- Language: Go
- Homepage:
- Size: 1.86 MB
- Stars: 0
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
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README
# [LeetCode.com](https://leetcode.com) (Free Exercises only)
The purpose of LeetCode is to provide you hands-on training on real coding interview questions. The Online Judge gives you immediate feedback on the correctness and efficiency of your algorithm which facilitates a great learning experience. Solutions to problem implemented in Go, as I am trying to have more practice in this language.
* [Progress](#progress)
* [Stats](#stats)
* [Solved Hard Problems](#solved---hard-problems)
* [Solved Medium Problems](#solved--medium-problems)
* [Solved Easy Problems](#solved--easy-problems)
* [Upcoming Problems](#solved-problems)
## Progress
▰▰▰▰▰▰▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱▱
## Stats
Difficulty | Total | Done | % |
------------------------------------|---------|--------|---------|
Easy | 529 | 61 | 12 % |
Medium | 1097 | 76 | 7 % |
Hard | 438 | 10 | 2 % |
Total Questions Available | 2064 | 147 | 7 % |
## Solved ☆☆☆ Hard Problems
ID | Problem | Topics
-----|-----------------------|-------------
1665 | [Minimum Initial Energy to Finish Tasks](Sort/1665-Minimum-Initial-Energy-to-Finish-Tasks) | `Greedy`, `Array`, `Sorting`
1383 | [Maximum Performance of a Team](Heap/1383-Maximum-Performance-of-a-Team) | `Greedy`, `Array`, `Sorting`, `Heap (Priority Queue)`
780 | [Reaching Points](Math/0780-Reaching-Points) | `Math`
479 | [Largest Palindrome Product](Math/0479-Largest-Palindrome-Product) | `Math`
239 | [Sliding Window Maximum](Heap/0239-Sliding-Window-Maximum) | `Queue`, `Array`, `Sliding Window`, `Monotonic Queue`, `Heap (Priority Queue)`
214 | [Shortest Palindrome](String/0214-Shortest-Palindrome) | `String`, `String Matching`, `Hash Function`, `Rolling Hash`
51 | [N-Queens](Backtracking/0051-N-Queens) | `Array`, `Backtracking`
37 | [Sudoku Solver](Backtracking/0037-Sudoku-Solver) | `Array`, `Backtracking`, `Matrix`
23 | [Merge k Sorted Lists](Linked_List/0023-Merge-k-Sorted-Lists) | `Linked List`, `Divide and Conquer`, `Heap (Priority Queue)`, `Merge Sort`
4 | [Median of Two Sorted Arrays](Divide_and_Conquer/0004-Median-of-Two-Sorted-Arrays) | `Array`, `Binary Search`, `Divide and Conquer`
### Solved ☆☆ Medium Problems
ID | Problem | Topics
-----|-----------------------|-------------
1419 | [Minimum Number of Frogs Croaking](String/1419-Minimum-Number-of-Frogs-Croaking) | `String`, `Counting`
1418 | [Display Table of Food Orders in a Restaurant](Hash_Table/1418-Display-Table-of-Food-Orders-in-a-Restaurant) | `Array`, `Hash Table`, `String`, `Ordered Set`, `Sorting`
1233 | [Remove Sub-Folders from the Filesystem](String/1233-Remove-Sub-Folders-from-the-Filesystem) | `Trie`, `Array`, `String`
1209 | [Remove All Adjacent Duplicates in String II](Stack/1209-Remove-All-Adjacent-Duplicates-in-String-II) | `Stack`, `String`
1146 | [Snapshot Array](Array/1146-Snapshot-Array) | `Design`, `Array`, `Hash Table`, `Binary Search`
1131 | [Maximum of Absolute Value Expression](Math/1131-Maximum-of-Absolute-Value-Expression) | `Array`, `Math`
1109 | [Corporate Flight Bookings](Array/1109-Corporate-Flight-Bookings) | `Array`, `Prefix Sum`
1094 | [Car Pooling](Greedy/1094-Car-Pooling) | `Array`, `Prefix Sum`, `Sorting`, `Simulation`, `Heap (Priority Queue)`
1093 | [Statistics from a Large Sample](Math/1093-Statistics-from-a-Large-Sample) | `Math`, `Two Pointers`, `Probability and Statistics`
1014 | [Best Sightseeing Pair](Array/1014-Best-Sightseeing-Pair) | `Array`, `Dynamic Programming`
1008 | [Construct Binary Search Tree from Preorder Traversal](Tree/1008-Construct-Binary-Search-Tree-from-Preorder-Traversal) | `Stack`, `Tree`, `Binary Search Tree`, `Array`, `Binary Tree`, `Monotonic Stack`
990 | [Satisfiability of Equality Equations](Union_Find/0990-Satisfiability-of-Equality-Equations) | `Union Find`, `Graph`, `Array`, `String`
973 | [K Closest Points to Origin](Sort/0973-K-Closest-Points-to-Origin) | `Geometry`, `Array`, `Math`, `Divide and Conquer`, `Quickselect`, `Sorting`, `Heap (Priority Queue)`
957 | [Prison Cells After N Days](Hash_Table/0957-Prison-Cells-After-N-Days) | `Bit Manipulation`, `Array`, `Hash Table`, `Math`
916 | [Word Subsets](String/0916-Word-Subsets) | `Array`, `Hash Table`, `String`
848 | [Shifting Letters](String/0848-Shifting-Letters) | `Array`, `String`
695 | [Max Area of Island](Depth-first_Search/0695-Max-Area-of-Island) | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
670 | [Maximum Swap](Array/0670-Maximum-Swap) | `Greedy`, `Math`
539 | [Minimum Time Difference](String/0539-Minimum-Time-Difference) | `Array`, `Math`, `String`, `Sorting`
537 | [Complex Number Multiplication](Math/0537-Complex-Number-Multiplication) | `Math`, `String`, `Simulation`
518 | [Coin Change 2](Dynamic_Programming/0518-Coin-Change-2) | `Array`, `Dynamic Programming`
477 | [Total Hamming Distance](Bit_Manipulation/0477-Total-Hamming-Distance) | `Bit Manipulation`, `Array`, `Math`
451 | [Sort Characters By Frequency](Sort/0451-Sort-Characters-By-Frequency) | `Hash Table`, `String`, `Bucket Sort`, `Counting`, `Sorting`, `Heap (Priority Queue)`
443 | [String Compression](String/0443-String-Compression) | `Two Pointers`, `String`
442 | [Find All Duplicates in an Array](Array/0442-Find-All-Duplicates-in-an-Array) | `Array`, `Hash Table`
386 | [Lexicographical Numbers](Unsorted/0386-Lexicographical-Numbers) | `Depth-First Search`, `Trie`
384 | [Shuffle an Array](Unsorted/0384-Shuffle-an-Array) | `Array`, `Math`, `Randomized`
322 | [Coin Change](Dynamic_Programming/0322-Coin-Change) | `Breadth-First Search`, `Array`, `Dynamic Programming`
313 | [Super Ugly Number](Math/0313-Super-Ugly-Number) | `Array`, `Hash Table`, `Math`, `Dynamic Programming`, `Heap (Priority Queue)`
275 | [H-Index II](Binary_Search/0275-H-Index-II) | `Array`, `Binary Search`
264 | [Ugly Number II](Math/0264-Ugly-Number-II) | `Hash Table`, `Math`, `Dynamic Programming`, `Heap (Priority Queue)`
220 | [Contains Duplicate III](Hash_Table/0220-Contains-Duplicate-III) | `Array`, `Bucket Sort`, `Ordered Set`, `Sorting`, `Sliding Window`
215 | [Kth Largest Element in an Array](Heap/0215-Kth-Largest-Element-in-an-Array) | `Array`, `Divide and Conquer`, `Quickselect`, `Sorting`, `Heap (Priority Queue)`
204 | [Count Primes](Hash_Table/0204-Count-Primes) | `Array`, `Math`, `Enumeration`, `Number Theory`
200 | [Number of Islands](Depth-first_Search/0200-Number-of-Islands) | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
198 | [House Robber](Dynamic_Programming/0198-House-Robber) | `Array`, `Dynamic Programming`
189 | [Rotate Array](Array/0189-Rotate-Array) | `Array`, `Math`, `Two Pointers`
179 | [Largest Number](Sort/0179-Largest-Number) | `Greedy`, `String`, `Sorting`
173 | [Binary Search Tree Iterator](Design/0173-Binary-Search-Tree-Iterator) | `Stack`, `Tree`, `Design`, `Binary Search Tree`, `Binary Tree`, `Iterator`
165 | [Compare Version Numbers](String/0165-Compare-Version-Numbers) | `Two Pointers`, `String`
151 | [Reverse Words in a String](String/0151-Reverse-Words-in-a-String) | `Two Pointers`, `String`
146 | [LRU Cache](Design/0146-LRU-Cache) | `Design`, `Hash Table`, `Linked List`, `Doubly-Linked List`
122 | [Best Time to Buy and Sell Stock II](Array/0122-Best-Time-to-Buy-and-Sell-Stock-II) | `Greedy`, `Array`, `Dynamic Programming`
120 | [Triangle](Dynamic_Programming/0120-Triangle) | `Array`, `Dynamic Programming`
114 | [Flatten Binary Tree to Linked List](Tree/0114-Flatten-Binary-Tree-to-Linked-List) | `Stack`, `Tree`, `Depth-First Search`, `Linked List`, `Binary Tree`
109 | [Convert Sorted List to Binary Search Tree](Linked_List/0109-Convert-Sorted-List-to-Binary-Search-Tree) | `Tree`, `Binary Search Tree`, `Linked List`, `Divide and Conquer`, `Binary Tree`
98 | [Validate Binary Search Tree](Tree/0098-Validate-Binary-Search-Tree) | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
97 | [Interleaving String](Dynamic_Programming/0097-Interleaving-String) | `String`, `Dynamic Programming`
78 | [Subsets](Array/0078-Subsets) | `Bit Manipulation`, `Array`, `Backtracking`
74 | [Search a 2D Matrix](Binary_Search/0074-Search-a-2D-Matrix) | `Array`, `Binary Search`, `Matrix`
64 | [Minimum Path Sum](Dynamic_Programming/0064-Minimum-Path-Sum) | `Array`, `Dynamic Programming`, `Matrix`
63 | [Unique Paths II](Dynamic_Programming/0063-Unique-Paths-II) | `Array`, `Dynamic Programming`, `Matrix`
62 | [Unique Paths](Dynamic_Programming/0062-Unique-Paths) | `Math`, `Dynamic Programming`, `Combinatorics`
61 | [Rotate List](Linked_List/0061-Rotate-List) | `Linked List`, `Two Pointers`
59 | [Spiral Matrix II](Array/0059-Spiral-Matrix-II) | `Array`, `Matrix`, `Simulation`
57 | [Insert Interval](Sort/0057-Insert-Interval) | `Array`
56 | [Merge Intervals](Sort/0056-Merge-Intervals) | `Array`, `Sorting`
54 | [Spiral Matrix](Array/0054-Spiral-Matrix) | `Array`, `Matrix`, `Simulation`
50 | [Pow(x, n)](Divide_and_Conquer/0050-Pow(x,-n)) | `Recursion`, `Math`
49 | [Group Anagrams](Hash_Table/0049-Group-Anagrams) | `Hash Table`, `String`, `Sorting`
47 | [Permutations II](Backtracking/0047-Permutations-II) | `Array`, `Backtracking`
46 | [Permutations](Backtracking/0046-Permutations) | `Array`, `Backtracking`
36 | [Valid Sudoku](Array/0036-Valid-Sudoku) | `Array`, `Hash Table`, `Matrix`
34 | [Find First and Last Position of Element in Sorted Array](Binary_Search/0034-Find-First-and-Last-Position-of-Element-in-Sorted-Array) | `Array`, `Binary Search`
33 | [Search in Rotated Sorted Array](Binary_Search/0033-Search-in-Rotated-Sorted-Array) | `Array`, `Binary Search`
31 | [Next Permutation](Array/0031-Next-Permutation) | `Array`, `Two Pointers`
22 | [Generate Parentheses](Backtracking/0022-Generate-Parentheses) | `String`, `Dynamic Programming`, `Backtracking`
17 | [Letter Combinations of a Phone Number](Backtracking/0017-Letter-Combinations-of-a-Phone-Number) | `Hash Table`, `String`, `Backtracking`
15 | [3Sum](Array/0015-3Sum) | `Array`, `Two Pointers`, `Sorting`
12 | [Integer to Roman](String/0012-Integer-to-Roman) | `Hash Table`, `Math`, `String`
11 | [Container With Most Water](Array/0011-Container-With-Most-Water) | `Greedy`, `Array`, `Two Pointers`
8 | [String to Integer (atoi)](Math/0008-String-to-Integer-(atoi)) | `String`
6 | [ZigZag Conversion](String/0006-ZigZag-Conversion) | `String`
5 | [Longest Palindromic Substring](String/0005-Longest-Palindromic-Substring) | `String`, `Dynamic Programming`
3 | [Longest Substring Without Repeating Characters](Hash_Table/0003-Longest-Substring-Without-Repeating-Characters) | `Hash Table`, `String`, `Sliding Window`
2 | [Add Two Numbers](Linked_List/0002-Add-Two-Numbers) | `Recursion`, `Linked List`, `Math`
## Solved ☆ Easy Problems
ID | Problem | Topics
-----|-----------------------|-------------
1360 | [Number of Days Between Two Dates](String/1360-Number-of-Days-Between-Two-Dates) | `Math`, `String`
1337 | [The K Weakest Rows in a Matrix](Heap/1337-The-K-Weakest-Rows-in-a-Matrix) | `Array`, `Binary Search`, `Matrix`, `Sorting`, `Heap (Priority Queue)`
1295 | [Find Numbers with Even Number of Digits](Array/1295-Find-Numbers-with-Even-Number-of-Digits) | `Array`
1232 | [Check If It Is a Straight Line](Math/1232-Check-If-It-Is-a-Straight-Line) | `Geometry`, `Array`, `Math`
1154 | [Day of the Year](String/1154-Day-of-the-Year) | `Math`, `String`
1128 | [Number of Equivalent Domino Pairs](Array/1128-Number-of-Equivalent-Domino-Pairs) | `Array`, `Hash Table`, `Counting`
1122 | [Relative Sort Array](Array/1122-Relative-Sort-Array) | `Array`, `Hash Table`, `Counting Sort`, `Sorting`
1108 | [Defanging an IP Address](String/1108-Defanging-an-IP-Address) | `String`
1047 | [Remove All Adjacent Duplicates In String](Stack/1047-Remove-All-Adjacent-Duplicates-In-String) | `Stack`, `String`
1046 | [Last Stone Weight](Heap/1046-Last-Stone-Weight) | `Array`, `Heap (Priority Queue)`
1030 | [Matrix Cells in Distance Order](Sort/1030-Matrix-Cells-in-Distance-Order) | `Geometry`, `Array`, `Math`, `Matrix`, `Sorting`
1009 | [Complement of Base 10 Integer](Math/1009-Complement-of-Base-10-Integer) | `Bit Manipulation`
961 | [N-Repeated Element in Size 2N Array](Hash_Table/0961-N-Repeated-Element-in-Size-2N-Array) | `Array`, `Hash Table`
917 | [Reverse Only Letters](String/0917-Reverse-Only-Letters) | `Two Pointers`, `String`
905 | [Sort Array By Parity](Array/0905-Sort-Array-By-Parity) | `Array`, `Two Pointers`, `Sorting`
766 | [Toeplitz Matrix](Array/0766-Toeplitz-Matrix) | `Array`, `Matrix`
704 | [Binary Search](Binary_Search/0704-Binary-Search) | `Array`, `Binary Search`
703 | [Kth Largest Element in a Stream](Heap/0703-Kth-Largest-Element-in-a-Stream) | `Tree`, `Design`, `Binary Search Tree`, `Binary Tree`, `Data Stream`, `Heap (Priority Queue)`
674 | [Longest Continuous Increasing Subsequence](Array/0674-Longest-Continuous-Increasing-Subsequence) | `Array`
557 | [Reverse Words in a String III](String/0557-Reverse-Words-in-a-String-III) | `Two Pointers`, `String`
520 | [Detect Capital](String/0520-Detect-Capital) | `String`
509 | [Fibonacci Number](Math/0509-Fibonacci-Number) | `Recursion`, `Memoization`, `Math`, `Dynamic Programming`
507 | [Perfect Number](Math/0507-Perfect-Number) | `Math`
506 | [Relative Ranks](Heap/0506-Relative-Ranks) | `Array`, `Sorting`, `Heap (Priority Queue)`
461 | [Hamming Distance](Bit_Manipulation/0461-Hamming-Distance) | `Bit Manipulation`
448 | [Find All Numbers Disappeared in an Array](Array/0448-Find-All-Numbers-Disappeared-in-an-Array) | `Array`, `Hash Table`
441 | [Arranging Coins](Math/0441-Arranging-Coins) | `Math`, `Binary Search`
412 | [Fizz Buzz](Unsorted/0412-Fizz-Buzz) | `Math`, `String`, `Simulation`
387 | [First Unique Character in a String](Hash_Table/0387-First-Unique-Character-in-a-String) | `Queue`, `Hash Table`, `String`, `Counting`
367 | [Valid Perfect Square](Math/0367-Valid-Perfect-Square) | `Math`, `Binary Search`
345 | [Reverse Vowels of a String](String/0345-Reverse-Vowels-of-a-String) | `Two Pointers`, `String`
344 | [Reverse String](String/0344-Reverse-String) | `Recursion`, `Two Pointers`, `String`
342 | [Power of Four](Bit_Manipulation/0342-Power-of-Four) | `Bit Manipulation`, `Recursion`, `Math`
338 | [Counting Bits](Bit_Manipulation/0338-Counting-Bits) | `Bit Manipulation`, `Dynamic Programming`
326 | [Power of Three](Math/0326-Power-of-Three) | `Recursion`, `Math`
263 | [Ugly Number](Math/0263-Ugly-Number) | `Math`
231 | [Power of Two](Bit_Manipulation/0231-Power-of-Two) | `Bit Manipulation`, `Recursion`, `Math`
219 | [Contains Duplicate II](Hash_Table/0219-Contains-Duplicate-II) | `Array`, `Hash Table`, `Sliding Window`
217 | [Contains Duplicate](Hash_Table/0217-Contains-Duplicate) | `Array`, `Hash Table`, `Sorting`
202 | [Happy Number](Hash_Table/0202-Happy-Number) | `Hash Table`, `Math`, `Two Pointers`
191 | [Number of 1 Bits](Bit_Manipulation/0191-Number-of-1-Bits) | `Bit Manipulation`
171 | [Excel Sheet Column Number](Math/0171-Excel-Sheet-Column-Number) | `Math`, `String`
168 | [Excel Sheet Column Title](Math/0168-Excel-Sheet-Column-Title) | `Math`, `String`
145 | [Binary Tree Postorder Traversal](Tree/0145-Binary-Tree-Postorder-Traversal) | `Stack`, `Tree`, `Depth-First Search`, `Binary Tree`
144 | [Binary Tree Preorder Traversal](Tree/0144-Binary-Tree-Preorder-Traversal) | `Stack`, `Tree`, `Depth-First Search`, `Binary Tree`
136 | [Single Number](Bit_Manipulation/0136-Single-Number) | `Bit Manipulation`, `Array`
125 | [Valid Palindrome](String/0125-Valid-Palindrome) | `Two Pointers`, `String`
121 | [Best Time to Buy and Sell Stock](Array/0121-Best-Time-to-Buy-and-Sell-Stock) | `Array`, `Dynamic Programming`
119 | [Pascal's Triangle II](Math/0119-Pascal's-Triangle-II) | `Array`, `Dynamic Programming`
118 | [Pascal's Triangle](Array/0118-Pascal's-Triangle) | `Array`, `Dynamic Programming`
108 | [Convert Sorted Array to Binary Search Tree](Tree/0108-Convert-Sorted-Array-to-Binary-Search-Tree) | `Tree`, `Binary Search Tree`, `Array`, `Divide and Conquer`, `Binary Tree`
100 | [Same Tree](Tree/0100-Same-Tree) | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
94 | [Binary Tree Inorder Traversal](Tree/0094-Binary-Tree-Inorder-Traversal) | `Stack`, `Tree`, `Depth-First Search`, `Binary Tree`
83 | [Remove Duplicates from Sorted List](Linked_List/0083-Remove-Duplicates-from-Sorted-List) | `Linked List`
69 | [Sqrt(x)](Math/0069-Sqrt(x)) | `Math`, `Binary Search`
26 | [Remove Duplicates from Sorted Array](Array/0026-Remove-Duplicates-from-Sorted-Array) | `Array`, `Two Pointers`
21 | [Merge Two Sorted Lists](Linked_List/0021-Merge-Two-Sorted-Lists) | `Recursion`, `Linked List`
20 | [Valid Parentheses](String/0020-Valid-Parentheses) | `Stack`, `String`
9 | [Palindrome Number](Math/0009-Palindrome-Number) | `Math`
7 | [Reverse Integer](Math/0007-Reverse-Integer) | `Math`
1 | [Two Sum](Array/0001-Two-Sum) | `Array`, `Hash Table`
## Unsolved Problems
ID | Problem @ LeetCode | Difficulty | Topics
-----|-----------------------|:-----------:|--------
2067 | [Number of Equal Count Substrings](https://leetcode.com/problems/number-of-equal-count-substrings) | Medium |
2066 | [Account Balance](https://leetcode.com/problems/account-balance) | Medium | `Database`
2065 | [Maximum Path Quality of a Graph](https://leetcode.com/problems/maximum-path-quality-of-a-graph) | Hard | `Graph`, `Array`, `Backtracking`
2064 | [Minimized Maximum of Products Distributed to Any Store](https://leetcode.com/problems/minimized-maximum-of-products-distributed-to-any-store) | Medium | `Array`, `Binary Search`
2062 | [Count Vowel Substrings of a String](https://leetcode.com/problems/count-vowel-substrings-of-a-string) | Easy | `Hash Table`, `String`
2061 | [Number of Spaces Cleaning Robot Cleaned](https://leetcode.com/problems/number-of-spaces-cleaning-robot-cleaned) | Medium |
2060 | [Check if an Original String Exists Given Two Encoded Strings](https://leetcode.com/problems/check-if-an-original-string-exists-given-two-encoded-strings) | Hard | `String`, `Dynamic Programming`
2059 | [Minimum Operations to Convert Number](https://leetcode.com/problems/minimum-operations-to-convert-number) | Medium | `Breadth-First Search`, `Array`
2058 | [Find the Minimum and Maximum Number of Nodes Between Critical Points](https://leetcode.com/problems/find-the-minimum-and-maximum-number-of-nodes-between-critical-points) | Medium | `Linked List`
2057 | [Smallest Index With Equal Value](https://leetcode.com/problems/smallest-index-with-equal-value) | Easy | `Array`
2056 | [Number of Valid Move Combinations On Chessboard](https://leetcode.com/problems/number-of-valid-move-combinations-on-chessboard) | Hard | `Array`, `String`, `Backtracking`, `Simulation`
2055 | [Plates Between Candles](https://leetcode.com/problems/plates-between-candles) | Medium | `Array`, `String`, `Binary Search`, `Prefix Sum`
2053 | [Kth Distinct String in an Array](https://leetcode.com/problems/kth-distinct-string-in-an-array) | Easy | `Array`, `Hash Table`, `String`, `Counting`
2052 | [Minimum Cost to Separate Sentence Into Rows](https://leetcode.com/problems/minimum-cost-to-separate-sentence-into-rows) | Medium | `Array`, `Dynamic Programming`
2051 | [The Category of Each Member in the Store](https://leetcode.com/problems/the-category-of-each-member-in-the-store) | Medium | `Database`
2050 | [Parallel Courses III](https://leetcode.com/problems/parallel-courses-iii) | Hard | `Graph`, `Topological Sort`, `Dynamic Programming`
2049 | [Count Nodes With the Highest Score](https://leetcode.com/problems/count-nodes-with-the-highest-score) | Medium | `Tree`, `Depth-First Search`, `Array`, `Binary Tree`
2048 | [Next Greater Numerically Balanced Number](https://leetcode.com/problems/next-greater-numerically-balanced-number) | Medium | `Math`, `Backtracking`, `Enumeration`
2047 | [Number of Valid Words in a Sentence](https://leetcode.com/problems/number-of-valid-words-in-a-sentence) | Easy | `String`
2046 | [Sort Linked List Already Sorted Using Absolute Values](https://leetcode.com/problems/sort-linked-list-already-sorted-using-absolute-values) | Medium | `Linked List`, `Two Pointers`, `Sorting`
2045 | [Second Minimum Time to Reach Destination](https://leetcode.com/problems/second-minimum-time-to-reach-destination) | Hard | `Breadth-First Search`, `Graph`, `Array`, `Shortest Path`
2044 | [Count Number of Maximum Bitwise-OR Subsets](https://leetcode.com/problems/count-number-of-maximum-bitwise-or-subsets) | Medium | `Bit Manipulation`, `Array`, `Backtracking`
2043 | [Simple Bank System](https://leetcode.com/problems/simple-bank-system) | Medium | `Design`, `Array`, `Hash Table`, `Simulation`
2042 | [Check if Numbers Are Ascending in a Sentence](https://leetcode.com/problems/check-if-numbers-are-ascending-in-a-sentence) | Easy | `String`
2041 | [Accepted Candidates From the Interviews](https://leetcode.com/problems/accepted-candidates-from-the-interviews) | Medium | `Database`
2040 | [Kth Smallest Product of Two Sorted Arrays](https://leetcode.com/problems/kth-smallest-product-of-two-sorted-arrays) | Hard | `Array`, `Binary Search`
2039 | [The Time When the Network Becomes Idle](https://leetcode.com/problems/the-time-when-the-network-becomes-idle) | Medium | `Breadth-First Search`, `Graph`, `Array`
2038 | [Remove Colored Pieces if Both Neighbors are the Same Color](https://leetcode.com/problems/remove-colored-pieces-if-both-neighbors-are-the-same-color) | Medium | `Greedy`, `Math`, `String`, `Game Theory`
2037 | [Minimum Number of Moves to Seat Everyone](https://leetcode.com/problems/minimum-number-of-moves-to-seat-everyone) | Easy | `Array`, `Sorting`
2036 | [Maximum Alternating Subarray Sum](https://leetcode.com/problems/maximum-alternating-subarray-sum) | Medium | `Array`, `Dynamic Programming`
2035 | [Partition Array Into Two Arrays to Minimize Sum Difference](https://leetcode.com/problems/partition-array-into-two-arrays-to-minimize-sum-difference) | Hard | `Bit Manipulation`, `Array`, `Two Pointers`, `Binary Search`, `Dynamic Programming`, `Bitmask`, `Ordered Set`
2034 | [Stock Price Fluctuation ](https://leetcode.com/problems/stock-price-fluctuation) | Medium | `Design`, `Hash Table`, `Ordered Set`, `Heap (Priority Queue)`
2033 | [Minimum Operations to Make a Uni-Value Grid](https://leetcode.com/problems/minimum-operations-to-make-a-uni-value-grid) | Medium | `Array`, `Math`, `Matrix`, `Sorting`
2032 | [Two Out of Three](https://leetcode.com/problems/two-out-of-three) | Easy | `Array`, `Hash Table`
2031 | [Count Subarrays With More Ones Than Zeros](https://leetcode.com/problems/count-subarrays-with-more-ones-than-zeros) | Medium | `Binary Indexed Tree`, `Segment Tree`, `Array`, `Binary Search`, `Divide and Conquer`, `Ordered Set`, `Merge Sort`
2030 | [Smallest K-Length Subsequence With Occurrences of a Letter](https://leetcode.com/problems/smallest-k-length-subsequence-with-occurrences-of-a-letter) | Hard | `Stack`, `Greedy`, `String`, `Monotonic Stack`
2029 | [Stone Game IX](https://leetcode.com/problems/stone-game-ix) | Medium | `Greedy`, `Array`, `Math`, `Counting`, `Game Theory`
2028 | [Find Missing Observations](https://leetcode.com/problems/find-missing-observations) | Medium | `Array`, `Math`, `Simulation`
2027 | [Minimum Moves to Convert String](https://leetcode.com/problems/minimum-moves-to-convert-string) | Easy | `Greedy`, `String`
2026 | [Low-Quality Problems](https://leetcode.com/problems/low-quality-problems) | Easy | `Database`
2025 | [Maximum Number of Ways to Partition an Array](https://leetcode.com/problems/maximum-number-of-ways-to-partition-an-array) | Hard | `Array`, `Hash Table`, `Counting`, `Enumeration`, `Prefix Sum`
2024 | [Maximize the Confusion of an Exam](https://leetcode.com/problems/maximize-the-confusion-of-an-exam) | Medium | `String`, `Binary Search`, `Prefix Sum`, `Sliding Window`
2023 | [Number of Pairs of Strings With Concatenation Equal to Target](https://leetcode.com/problems/number-of-pairs-of-strings-with-concatenation-equal-to-target) | Medium | `Array`, `String`
2022 | [Convert 1D Array Into 2D Array](https://leetcode.com/problems/convert-1d-array-into-2d-array) | Easy | `Array`, `Matrix`, `Simulation`
2021 | [Brightest Position on Street](https://leetcode.com/problems/brightest-position-on-street) | Medium | `Array`, `Ordered Set`, `Prefix Sum`
2020 | [Number of Accounts That Did Not Stream](https://leetcode.com/problems/number-of-accounts-that-did-not-stream) | Medium | `Database`
2019 | [The Score of Students Solving Math Expression](https://leetcode.com/problems/the-score-of-students-solving-math-expression) | Hard | `Stack`, `Memoization`, `Array`, `Math`, `String`, `Dynamic Programming`
2018 | [Check if Word Can Be Placed In Crossword](https://leetcode.com/problems/check-if-word-can-be-placed-in-crossword) | Medium | `Array`, `Enumeration`, `Matrix`
2017 | [Grid Game](https://leetcode.com/problems/grid-game) | Medium | `Array`, `Matrix`, `Prefix Sum`
2016 | [Maximum Difference Between Increasing Elements](https://leetcode.com/problems/maximum-difference-between-increasing-elements) | Easy | `Array`
2015 | [Average Height of Buildings in Each Segment](https://leetcode.com/problems/average-height-of-buildings-in-each-segment) | Medium | `Greedy`, `Array`, `Sorting`, `Heap (Priority Queue)`
2014 | [Longest Subsequence Repeated k Times](https://leetcode.com/problems/longest-subsequence-repeated-k-times) | Hard | `Greedy`, `String`, `Backtracking`, `Counting`, `Enumeration`
2013 | [Detect Squares](https://leetcode.com/problems/detect-squares) | Medium | `Design`, `Array`, `Hash Table`, `Counting`
2012 | [Sum of Beauty in the Array](https://leetcode.com/problems/sum-of-beauty-in-the-array) | Medium | `Array`
2011 | [Final Value of Variable After Performing Operations](https://leetcode.com/problems/final-value-of-variable-after-performing-operations) | Easy | `Array`, `String`, `Simulation`
2010 | [The Number of Seniors and Juniors to Join the Company II](https://leetcode.com/problems/the-number-of-seniors-and-juniors-to-join-the-company-ii) | Hard |
2009 | [Minimum Number of Operations to Make Array Continuous](https://leetcode.com/problems/minimum-number-of-operations-to-make-array-continuous) | Hard | `Array`, `Binary Search`
2008 | [Maximum Earnings From Taxi](https://leetcode.com/problems/maximum-earnings-from-taxi) | Medium | `Array`, `Binary Search`, `Dynamic Programming`, `Sorting`
2007 | [Find Original Array From Doubled Array](https://leetcode.com/problems/find-original-array-from-doubled-array) | Medium | `Greedy`, `Array`, `Hash Table`, `Sorting`
2006 | [Count Number of Pairs With Absolute Difference K](https://leetcode.com/problems/count-number-of-pairs-with-absolute-difference-k) | Easy | `Array`
2005 | [Subtree Removal Game with Fibonacci Tree](https://leetcode.com/problems/subtree-removal-game-with-fibonacci-tree) | Hard |
2004 | [The Number of Seniors and Juniors to Join the Company](https://leetcode.com/problems/the-number-of-seniors-and-juniors-to-join-the-company) | Hard |
2003 | [Smallest Missing Genetic Value in Each Subtree](https://leetcode.com/problems/smallest-missing-genetic-value-in-each-subtree) | Hard | `Tree`, `Depth-First Search`, `Union Find`, `Dynamic Programming`
2002 | [Maximum Product of the Length of Two Palindromic Subsequences](https://leetcode.com/problems/maximum-product-of-the-length-of-two-palindromic-subsequences) | Medium | `Bit Manipulation`, `String`, `Dynamic Programming`, `Backtracking`, `Bitmask`
2001 | [Number of Pairs of Interchangeable Rectangles](https://leetcode.com/problems/number-of-pairs-of-interchangeable-rectangles) | Medium | `Array`, `Hash Table`, `Math`, `Counting`, `Number Theory`
2000 | [Reverse Prefix of Word](https://leetcode.com/problems/reverse-prefix-of-word) | Easy | `Two Pointers`, `String`
1999 | [Smallest Greater Multiple Made of Two Digits](https://leetcode.com/problems/smallest-greater-multiple-made-of-two-digits) | Medium |
1998 | [GCD Sort of an Array](https://leetcode.com/problems/gcd-sort-of-an-array) | Hard | `Union Find`, `Array`, `Math`, `Sorting`
1997 | [First Day Where You Have Been in All the Rooms](https://leetcode.com/problems/first-day-where-you-have-been-in-all-the-rooms) | Medium | `Array`, `Dynamic Programming`
1996 | [The Number of Weak Characters in the Game](https://leetcode.com/problems/the-number-of-weak-characters-in-the-game) | Medium | `Stack`, `Greedy`, `Array`, `Sorting`, `Monotonic Stack`
1995 | [Count Special Quadruplets](https://leetcode.com/problems/count-special-quadruplets) | Easy | `Array`, `Enumeration`
1994 | [The Number of Good Subsets](https://leetcode.com/problems/the-number-of-good-subsets) | Hard | `Bit Manipulation`, `Array`, `Math`, `Dynamic Programming`, `Bitmask`
1993 | [Operations on Tree](https://leetcode.com/problems/operations-on-tree) | Medium | `Tree`, `Breadth-First Search`, `Design`, `Hash Table`
1992 | [Find All Groups of Farmland](https://leetcode.com/problems/find-all-groups-of-farmland) | Medium | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`
1991 | [Find the Middle Index in Array](https://leetcode.com/problems/find-the-middle-index-in-array) | Easy | `Array`, `Prefix Sum`
1990 | [Count the Number of Experiments](https://leetcode.com/problems/count-the-number-of-experiments) | Easy |
1989 | [Maximum Number of People That Can Be Caught in Tag](https://leetcode.com/problems/maximum-number-of-people-that-can-be-caught-in-tag) | Medium |
1988 | [Find Cutoff Score for Each School](https://leetcode.com/problems/find-cutoff-score-for-each-school) | Medium |
1987 | [Number of Unique Good Subsequences](https://leetcode.com/problems/number-of-unique-good-subsequences) | Hard | `String`, `Dynamic Programming`
1986 | [Minimum Number of Work Sessions to Finish the Tasks](https://leetcode.com/problems/minimum-number-of-work-sessions-to-finish-the-tasks) | Medium | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
1985 | [Find the Kth Largest Integer in the Array](https://leetcode.com/problems/find-the-kth-largest-integer-in-the-array) | Medium | `Array`, `String`, `Divide and Conquer`, `Quickselect`, `Sorting`, `Heap (Priority Queue)`
1984 | [Minimum Difference Between Highest and Lowest of K Scores](https://leetcode.com/problems/minimum-difference-between-highest-and-lowest-of-k-scores) | Easy | `Array`, `Sorting`
1983 | [Widest Pair of Indices With Equal Range Sum](https://leetcode.com/problems/widest-pair-of-indices-with-equal-range-sum) | Medium |
1982 | [Find Array Given Subset Sums](https://leetcode.com/problems/find-array-given-subset-sums) | Hard | `Array`, `Divide and Conquer`
1981 | [Minimize the Difference Between Target and Chosen Elements](https://leetcode.com/problems/minimize-the-difference-between-target-and-chosen-elements) | Medium | `Array`, `Dynamic Programming`, `Matrix`
1980 | [Find Unique Binary String](https://leetcode.com/problems/find-unique-binary-string) | Medium | `Array`, `String`, `Backtracking`
1979 | [Find Greatest Common Divisor of Array](https://leetcode.com/problems/find-greatest-common-divisor-of-array) | Easy | `Array`, `Math`
1978 | [Employees Whose Manager Left the Company](https://leetcode.com/problems/employees-whose-manager-left-the-company) | Easy |
1977 | [Number of Ways to Separate Numbers](https://leetcode.com/problems/number-of-ways-to-separate-numbers) | Hard | `String`, `Dynamic Programming`, `Suffix Array`
1976 | [Number of Ways to Arrive at Destination](https://leetcode.com/problems/number-of-ways-to-arrive-at-destination) | Medium | `Graph`, `Topological Sort`, `Dynamic Programming`, `Shortest Path`
1975 | [Maximum Matrix Sum](https://leetcode.com/problems/maximum-matrix-sum) | Medium | `Greedy`, `Array`, `Matrix`
1974 | [Minimum Time to Type Word Using Special Typewriter](https://leetcode.com/problems/minimum-time-to-type-word-using-special-typewriter) | Easy | `Greedy`, `String`
1973 | [Count Nodes Equal to Sum of Descendants](https://leetcode.com/problems/count-nodes-equal-to-sum-of-descendants) | Medium |
1972 | [First and Last Call On the Same Day](https://leetcode.com/problems/first-and-last-call-on-the-same-day) | Hard | `Database`
1971 | [Find if Path Exists in Graph](https://leetcode.com/problems/find-if-path-exists-in-graph) | Easy | `Depth-First Search`, `Breadth-First Search`, `Graph`
1970 | [Last Day Where You Can Still Cross](https://leetcode.com/problems/last-day-where-you-can-still-cross) | Hard | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Binary Search`, `Matrix`
1969 | [Minimum Non-Zero Product of the Array Elements](https://leetcode.com/problems/minimum-non-zero-product-of-the-array-elements) | Medium | `Greedy`, `Recursion`, `Math`
1968 | [Array With Elements Not Equal to Average of Neighbors](https://leetcode.com/problems/array-with-elements-not-equal-to-average-of-neighbors) | Medium | `Greedy`, `Array`, `Sorting`
1967 | [Number of Strings That Appear as Substrings in Word](https://leetcode.com/problems/number-of-strings-that-appear-as-substrings-in-word) | Easy | `String`
1966 | [Binary Searchable Numbers in an Unsorted Array](https://leetcode.com/problems/binary-searchable-numbers-in-an-unsorted-array) | Medium |
1965 | [Employees With Missing Information](https://leetcode.com/problems/employees-with-missing-information) | Easy | `Database`
1964 | [Find the Longest Valid Obstacle Course at Each Position](https://leetcode.com/problems/find-the-longest-valid-obstacle-course-at-each-position) | Hard | `Binary Indexed Tree`, `Array`, `Binary Search`
1963 | [Minimum Number of Swaps to Make the String Balanced](https://leetcode.com/problems/minimum-number-of-swaps-to-make-the-string-balanced) | Medium | `Stack`, `Greedy`, `Two Pointers`, `String`
1962 | [Remove Stones to Minimize the Total](https://leetcode.com/problems/remove-stones-to-minimize-the-total) | Medium | `Array`, `Heap (Priority Queue)`
1961 | [Check If String Is a Prefix of Array](https://leetcode.com/problems/check-if-string-is-a-prefix-of-array) | Easy | `Array`, `String`
1960 | [Maximum Product of the Length of Two Palindromic Substrings](https://leetcode.com/problems/maximum-product-of-the-length-of-two-palindromic-substrings) | Hard | `String`, `Hash Function`, `Rolling Hash`
1959 | [Minimum Total Space Wasted With K Resizing Operations](https://leetcode.com/problems/minimum-total-space-wasted-with-k-resizing-operations) | Medium | `Array`, `Dynamic Programming`
1958 | [Check if Move is Legal](https://leetcode.com/problems/check-if-move-is-legal) | Medium | `Array`, `Enumeration`, `Matrix`
1957 | [Delete Characters to Make Fancy String](https://leetcode.com/problems/delete-characters-to-make-fancy-string) | Easy | `String`
1956 | [Minimum Time For K Virus Variants to Spread](https://leetcode.com/problems/minimum-time-for-k-virus-variants-to-spread) | Hard | `Geometry`, `Array`, `Math`, `Binary Search`, `Enumeration`
1955 | [Count Number of Special Subsequences](https://leetcode.com/problems/count-number-of-special-subsequences) | Hard | `Array`, `Dynamic Programming`
1954 | [Minimum Garden Perimeter to Collect Enough Apples](https://leetcode.com/problems/minimum-garden-perimeter-to-collect-enough-apples) | Medium | `Math`, `Binary Search`
1953 | [Maximum Number of Weeks for Which You Can Work](https://leetcode.com/problems/maximum-number-of-weeks-for-which-you-can-work) | Medium | `Greedy`, `Array`
1952 | [Three Divisors](https://leetcode.com/problems/three-divisors) | Easy | `Math`
1951 | [All the Pairs With the Maximum Number of Common Followers](https://leetcode.com/problems/all-the-pairs-with-the-maximum-number-of-common-followers) | Medium | `Database`
1950 | [Maximum of Minimum Values in All Subarrays](https://leetcode.com/problems/maximum-of-minimum-values-in-all-subarrays) | Medium |
1949 | [Strong Friendship](https://leetcode.com/problems/strong-friendship) | Medium | `Database`
1948 | [Delete Duplicate Folders in System](https://leetcode.com/problems/delete-duplicate-folders-in-system) | Hard | `Trie`, `Array`, `Hash Table`, `String`, `Hash Function`
1947 | [Maximum Compatibility Score Sum](https://leetcode.com/problems/maximum-compatibility-score-sum) | Medium | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
1946 | [Largest Number After Mutating Substring](https://leetcode.com/problems/largest-number-after-mutating-substring) | Medium | `Greedy`, `Array`, `String`
1945 | [Sum of Digits of String After Convert](https://leetcode.com/problems/sum-of-digits-of-string-after-convert) | Easy | `String`, `Simulation`
1944 | [Number of Visible People in a Queue](https://leetcode.com/problems/number-of-visible-people-in-a-queue) | Hard | `Stack`, `Array`, `Monotonic Stack`
1943 | [Describe the Painting](https://leetcode.com/problems/describe-the-painting) | Medium | `Array`, `Prefix Sum`
1942 | [The Number of the Smallest Unoccupied Chair](https://leetcode.com/problems/the-number-of-the-smallest-unoccupied-chair) | Medium | `Array`, `Ordered Set`, `Heap (Priority Queue)`
1941 | [Check if All Characters Have Equal Number of Occurrences](https://leetcode.com/problems/check-if-all-characters-have-equal-number-of-occurrences) | Easy | `Hash Table`, `String`, `Counting`
1940 | [Longest Common Subsequence Between Sorted Arrays](https://leetcode.com/problems/longest-common-subsequence-between-sorted-arrays) | Medium | `Array`, `Hash Table`, `Counting`
1939 | [Users That Actively Request Confirmation Messages](https://leetcode.com/problems/users-that-actively-request-confirmation-messages) | Easy | `Database`
1938 | [Maximum Genetic Difference Query](https://leetcode.com/problems/maximum-genetic-difference-query) | Hard |
1937 | [Maximum Number of Points with Cost](https://leetcode.com/problems/maximum-number-of-points-with-cost) | Medium |
1936 | [Add Minimum Number of Rungs](https://leetcode.com/problems/add-minimum-number-of-rungs) | Medium |
1935 | [Maximum Number of Words You Can Type](https://leetcode.com/problems/maximum-number-of-words-you-can-type) | Easy | `Hash Table`, `String`
1934 | [Confirmation Rate](https://leetcode.com/problems/confirmation-rate) | Medium | `Database`
1933 | [Check if String Is Decomposable Into Value-Equal Substrings](https://leetcode.com/problems/check-if-string-is-decomposable-into-value-equal-substrings) | Easy | `String`
1932 | [Merge BSTs to Create Single BST](https://leetcode.com/problems/merge-bsts-to-create-single-bst) | Hard | `Tree`, `Depth-First Search`, `Hash Table`, `Binary Search`, `Binary Tree`
1931 | [Painting a Grid With Three Different Colors](https://leetcode.com/problems/painting-a-grid-with-three-different-colors) | Hard | `Dynamic Programming`
1930 | [Unique Length-3 Palindromic Subsequences](https://leetcode.com/problems/unique-length-3-palindromic-subsequences) | Medium | `Hash Table`, `String`, `Prefix Sum`
1929 | [Concatenation of Array](https://leetcode.com/problems/concatenation-of-array) | Easy | `Array`
1928 | [Minimum Cost to Reach Destination in Time](https://leetcode.com/problems/minimum-cost-to-reach-destination-in-time) | Hard | `Graph`, `Dynamic Programming`
1927 | [Sum Game](https://leetcode.com/problems/sum-game) | Medium | `Greedy`, `Math`, `Game Theory`
1926 | [Nearest Exit from Entrance in Maze](https://leetcode.com/problems/nearest-exit-from-entrance-in-maze) | Medium | `Breadth-First Search`, `Array`, `Matrix`
1925 | [Count Square Sum Triples](https://leetcode.com/problems/count-square-sum-triples) | Easy | `Math`, `Enumeration`
1924 | [Erect the Fence II](https://leetcode.com/problems/erect-the-fence-ii) | Hard | `Geometry`, `Array`, `Math`
1923 | [Longest Common Subpath](https://leetcode.com/problems/longest-common-subpath) | Hard | `Array`, `Binary Search`, `Suffix Array`, `Hash Function`, `Rolling Hash`
1922 | [Count Good Numbers](https://leetcode.com/problems/count-good-numbers) | Medium | `Recursion`, `Math`
1921 | [Eliminate Maximum Number of Monsters](https://leetcode.com/problems/eliminate-maximum-number-of-monsters) | Medium | `Greedy`, `Array`, `Sorting`
1920 | [Build Array from Permutation](https://leetcode.com/problems/build-array-from-permutation) | Easy | `Array`, `Simulation`
1919 | [Leetcodify Similar Friends](https://leetcode.com/problems/leetcodify-similar-friends) | Hard | `Database`
1918 | [Kth Smallest Subarray Sum](https://leetcode.com/problems/kth-smallest-subarray-sum) | Medium | `Array`, `Binary Search`, `Sliding Window`
1917 | [Leetcodify Friends Recommendations](https://leetcode.com/problems/leetcodify-friends-recommendations) | Hard | `Database`
1916 | [Count Ways to Build Rooms in an Ant Colony](https://leetcode.com/problems/count-ways-to-build-rooms-in-an-ant-colony) | Hard | `Tree`, `Graph`, `Topological Sort`, `Math`, `Dynamic Programming`, `Combinatorics`
1915 | [Number of Wonderful Substrings](https://leetcode.com/problems/number-of-wonderful-substrings) | Medium | `Bit Manipulation`, `Hash Table`, `String`, `Prefix Sum`
1914 | [Cyclically Rotating a Grid](https://leetcode.com/problems/cyclically-rotating-a-grid) | Medium | `Array`, `Matrix`, `Simulation`
1913 | [Maximum Product Difference Between Two Pairs](https://leetcode.com/problems/maximum-product-difference-between-two-pairs) | Easy | `Array`, `Sorting`
1912 | [Design Movie Rental System](https://leetcode.com/problems/design-movie-rental-system) | Hard | `Design`, `Array`, `Hash Table`, `Ordered Set`, `Heap (Priority Queue)`
1911 | [Maximum Alternating Subsequence Sum](https://leetcode.com/problems/maximum-alternating-subsequence-sum) | Medium | `Array`, `Dynamic Programming`
1910 | [Remove All Occurrences of a Substring](https://leetcode.com/problems/remove-all-occurrences-of-a-substring) | Medium | `String`
1909 | [Remove One Element to Make the Array Strictly Increasing](https://leetcode.com/problems/remove-one-element-to-make-the-array-strictly-increasing) | Easy | `Array`
1908 | [Game of Nim](https://leetcode.com/problems/game-of-nim) | Medium | `Bit Manipulation`, `Brainteaser`, `Array`, `Math`, `Dynamic Programming`, `Game Theory`
1907 | [Count Salary Categories](https://leetcode.com/problems/count-salary-categories) | Medium | `Database`
1906 | [Minimum Absolute Difference Queries](https://leetcode.com/problems/minimum-absolute-difference-queries) | Medium | `Array`, `Hash Table`
1905 | [Count Sub Islands](https://leetcode.com/problems/count-sub-islands) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
1904 | [The Number of Full Rounds You Have Played](https://leetcode.com/problems/the-number-of-full-rounds-you-have-played) | Medium | `Math`, `String`
1903 | [Largest Odd Number in String](https://leetcode.com/problems/largest-odd-number-in-string) | Easy | `Greedy`, `Math`, `String`
1902 | [Depth of BST Given Insertion Order](https://leetcode.com/problems/depth-of-bst-given-insertion-order) | Medium | `Tree`, `Binary Search Tree`, `Binary Tree`, `Ordered Set`
1901 | [Find a Peak Element II](https://leetcode.com/problems/find-a-peak-element-ii) | Medium | `Array`, `Binary Search`, `Divide and Conquer`, `Matrix`
1900 | [The Earliest and Latest Rounds Where Players Compete](https://leetcode.com/problems/the-earliest-and-latest-rounds-where-players-compete) | Hard | `Memoization`, `Dynamic Programming`
1899 | [Merge Triplets to Form Target Triplet](https://leetcode.com/problems/merge-triplets-to-form-target-triplet) | Medium | `Greedy`, `Array`
1898 | [Maximum Number of Removable Characters](https://leetcode.com/problems/maximum-number-of-removable-characters) | Medium | `Array`, `String`, `Binary Search`
1897 | [Redistribute Characters to Make All Strings Equal](https://leetcode.com/problems/redistribute-characters-to-make-all-strings-equal) | Easy | `Hash Table`, `String`, `Counting`
1896 | [Minimum Cost to Change the Final Value of Expression](https://leetcode.com/problems/minimum-cost-to-change-the-final-value-of-expression) | Hard | `Stack`, `Math`, `String`, `Dynamic Programming`
1895 | [Largest Magic Square](https://leetcode.com/problems/largest-magic-square) | Medium | `Array`, `Matrix`, `Prefix Sum`
1894 | [Find the Student that Will Replace the Chalk](https://leetcode.com/problems/find-the-student-that-will-replace-the-chalk) | Medium | `Array`, `Binary Search`, `Prefix Sum`, `Simulation`
1893 | [Check if All the Integers in a Range Are Covered](https://leetcode.com/problems/check-if-all-the-integers-in-a-range-are-covered) | Easy | `Array`, `Hash Table`, `Prefix Sum`
1892 | [Page Recommendations II](https://leetcode.com/problems/page-recommendations-ii) | Hard | `Database`
1891 | [Cutting Ribbons](https://leetcode.com/problems/cutting-ribbons) | Medium | `Array`, `Binary Search`
1890 | [The Latest Login in 2020](https://leetcode.com/problems/the-latest-login-in-2020) | Easy | `Database`
1889 | [Minimum Space Wasted From Packaging](https://leetcode.com/problems/minimum-space-wasted-from-packaging) | Hard | `Array`, `Binary Search`, `Prefix Sum`, `Sorting`
1888 | [Minimum Number of Flips to Make the Binary String Alternating](https://leetcode.com/problems/minimum-number-of-flips-to-make-the-binary-string-alternating) | Medium | `Greedy`, `String`
1887 | [Reduction Operations to Make the Array Elements Equal](https://leetcode.com/problems/reduction-operations-to-make-the-array-elements-equal) | Medium | `Array`, `Sorting`
1886 | [Determine Whether Matrix Can Be Obtained By Rotation](https://leetcode.com/problems/determine-whether-matrix-can-be-obtained-by-rotation) | Easy | `Array`, `Matrix`
1885 | [Count Pairs in Two Arrays](https://leetcode.com/problems/count-pairs-in-two-arrays) | Medium | `Array`, `Binary Search`, `Sorting`
1884 | [Egg Drop With 2 Eggs and N Floors](https://leetcode.com/problems/egg-drop-with-2-eggs-and-n-floors) | Medium | `Math`, `Dynamic Programming`
1883 | [Minimum Skips to Arrive at Meeting On Time](https://leetcode.com/problems/minimum-skips-to-arrive-at-meeting-on-time) | Hard | `Array`, `Dynamic Programming`
1882 | [Process Tasks Using Servers](https://leetcode.com/problems/process-tasks-using-servers) | Medium | `Array`, `Heap (Priority Queue)`
1881 | [Maximum Value after Insertion](https://leetcode.com/problems/maximum-value-after-insertion) | Medium | `Greedy`, `String`
1880 | [Check if Word Equals Summation of Two Words](https://leetcode.com/problems/check-if-word-equals-summation-of-two-words) | Easy | `String`
1879 | [Minimum XOR Sum of Two Arrays](https://leetcode.com/problems/minimum-xor-sum-of-two-arrays) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Bitmask`
1878 | [Get Biggest Three Rhombus Sums in a Grid](https://leetcode.com/problems/get-biggest-three-rhombus-sums-in-a-grid) | Medium | `Array`, `Math`, `Matrix`, `Prefix Sum`, `Sorting`, `Heap (Priority Queue)`
1877 | [Minimize Maximum Pair Sum in Array](https://leetcode.com/problems/minimize-maximum-pair-sum-in-array) | Medium | `Greedy`, `Array`, `Two Pointers`, `Sorting`
1876 | [Substrings of Size Three with Distinct Characters](https://leetcode.com/problems/substrings-of-size-three-with-distinct-characters) | Easy | `Hash Table`, `String`, `Counting`, `Sliding Window`
1875 | [Group Employees of the Same Salary](https://leetcode.com/problems/group-employees-of-the-same-salary) | Medium | `Database`
1874 | [Minimize Product Sum of Two Arrays](https://leetcode.com/problems/minimize-product-sum-of-two-arrays) | Medium | `Greedy`, `Array`, `Sorting`
1873 | [Calculate Special Bonus](https://leetcode.com/problems/calculate-special-bonus) | Easy | `Database`
1872 | [Stone Game VIII](https://leetcode.com/problems/stone-game-viii) | Hard | `Array`, `Math`, `Dynamic Programming`, `Game Theory`, `Prefix Sum`
1871 | [Jump Game VII](https://leetcode.com/problems/jump-game-vii) | Medium | `Two Pointers`, `String`, `Prefix Sum`
1870 | [Minimum Speed to Arrive on Time](https://leetcode.com/problems/minimum-speed-to-arrive-on-time) | Medium | `Array`, `Binary Search`
1869 | [Longer Contiguous Segments of Ones than Zeros](https://leetcode.com/problems/longer-contiguous-segments-of-ones-than-zeros) | Easy | `String`
1868 | [Product of Two Run-Length Encoded Arrays](https://leetcode.com/problems/product-of-two-run-length-encoded-arrays) | Medium | `Array`, `Two Pointers`
1867 | [Orders With Maximum Quantity Above Average](https://leetcode.com/problems/orders-with-maximum-quantity-above-average) | Medium | `Database`
1866 | [Number of Ways to Rearrange Sticks With K Sticks Visible](https://leetcode.com/problems/number-of-ways-to-rearrange-sticks-with-k-sticks-visible) | Hard | `Math`, `Dynamic Programming`, `Combinatorics`
1865 | [Finding Pairs With a Certain Sum](https://leetcode.com/problems/finding-pairs-with-a-certain-sum) | Medium | `Design`, `Array`, `Hash Table`
1864 | [Minimum Number of Swaps to Make the Binary String Alternating](https://leetcode.com/problems/minimum-number-of-swaps-to-make-the-binary-string-alternating) | Medium | `Greedy`, `String`
1863 | [Sum of All Subset XOR Totals](https://leetcode.com/problems/sum-of-all-subset-xor-totals) | Easy | `Bit Manipulation`, `Array`, `Backtracking`
1862 | [Sum of Floored Pairs](https://leetcode.com/problems/sum-of-floored-pairs) | Hard | `Array`, `Math`, `Binary Search`, `Prefix Sum`
1861 | [Rotating the Box](https://leetcode.com/problems/rotating-the-box) | Medium | `Array`, `Two Pointers`, `Matrix`
1860 | [Incremental Memory Leak](https://leetcode.com/problems/incremental-memory-leak) | Medium | `Simulation`
1859 | [Sorting the Sentence](https://leetcode.com/problems/sorting-the-sentence) | Easy | `String`, `Sorting`
1858 | [Longest Word With All Prefixes](https://leetcode.com/problems/longest-word-with-all-prefixes) | Medium | `Depth-First Search`, `Trie`
1857 | [Largest Color Value in a Directed Graph](https://leetcode.com/problems/largest-color-value-in-a-directed-graph) | Hard | `Graph`, `Topological Sort`, `Memoization`, `Hash Table`, `Dynamic Programming`, `Counting`
1856 | [Maximum Subarray Min-Product](https://leetcode.com/problems/maximum-subarray-min-product) | Medium | `Stack`, `Array`, `Prefix Sum`, `Monotonic Stack`
1855 | [Maximum Distance Between a Pair of Values](https://leetcode.com/problems/maximum-distance-between-a-pair-of-values) | Medium | `Greedy`, `Array`, `Two Pointers`, `Binary Search`
1854 | [Maximum Population Year](https://leetcode.com/problems/maximum-population-year) | Easy | `Array`, `Counting`
1853 | [Convert Date Format](https://leetcode.com/problems/convert-date-format) | Easy | `Database`
1852 | [Distinct Numbers in Each Subarray](https://leetcode.com/problems/distinct-numbers-in-each-subarray) | Medium | `Array`, `Hash Table`, `Sliding Window`
1851 | [Minimum Interval to Include Each Query](https://leetcode.com/problems/minimum-interval-to-include-each-query) | Hard | `Array`, `Binary Search`, `Sorting`, `Line Sweep`, `Heap (Priority Queue)`
1850 | [Minimum Adjacent Swaps to Reach the Kth Smallest Number](https://leetcode.com/problems/minimum-adjacent-swaps-to-reach-the-kth-smallest-number) | Medium | `Greedy`, `Two Pointers`, `String`
1849 | [Splitting a String Into Descending Consecutive Values](https://leetcode.com/problems/splitting-a-string-into-descending-consecutive-values) | Medium | `String`, `Backtracking`
1848 | [Minimum Distance to the Target Element](https://leetcode.com/problems/minimum-distance-to-the-target-element) | Easy | `Array`
1847 | [Closest Room](https://leetcode.com/problems/closest-room) | Hard | `Array`, `Binary Search`, `Sorting`
1846 | [Maximum Element After Decreasing and Rearranging](https://leetcode.com/problems/maximum-element-after-decreasing-and-rearranging) | Medium | `Greedy`, `Array`, `Sorting`
1845 | [Seat Reservation Manager](https://leetcode.com/problems/seat-reservation-manager) | Medium | `Design`, `Heap (Priority Queue)`
1844 | [Replace All Digits with Characters](https://leetcode.com/problems/replace-all-digits-with-characters) | Easy | `String`
1843 | [Suspicious Bank Accounts](https://leetcode.com/problems/suspicious-bank-accounts) | Medium | `Database`
1842 | [Next Palindrome Using Same Digits](https://leetcode.com/problems/next-palindrome-using-same-digits) | Hard | `Two Pointers`, `String`
1841 | [League Statistics](https://leetcode.com/problems/league-statistics) | Medium | `Database`
1840 | [Maximum Building Height](https://leetcode.com/problems/maximum-building-height) | Hard | `Array`, `Math`
1839 | [Longest Substring Of All Vowels in Order](https://leetcode.com/problems/longest-substring-of-all-vowels-in-order) | Medium | `String`, `Sliding Window`
1838 | [Frequency of the Most Frequent Element](https://leetcode.com/problems/frequency-of-the-most-frequent-element) | Medium | `Array`, `Binary Search`, `Prefix Sum`, `Sliding Window`
1837 | [Sum of Digits in Base K](https://leetcode.com/problems/sum-of-digits-in-base-k) | Easy | `Math`
1836 | [Remove Duplicates From an Unsorted Linked List](https://leetcode.com/problems/remove-duplicates-from-an-unsorted-linked-list) | Medium | `Hash Table`, `Linked List`
1835 | [Find XOR Sum of All Pairs Bitwise AND](https://leetcode.com/problems/find-xor-sum-of-all-pairs-bitwise-and) | Hard | `Bit Manipulation`, `Array`, `Math`
1834 | [Single-Threaded CPU](https://leetcode.com/problems/single-threaded-cpu) | Medium | `Array`, `Sorting`, `Heap (Priority Queue)`
1833 | [Maximum Ice Cream Bars](https://leetcode.com/problems/maximum-ice-cream-bars) | Medium | `Greedy`, `Array`, `Sorting`
1832 | [Check if the Sentence Is Pangram](https://leetcode.com/problems/check-if-the-sentence-is-pangram) | Easy | `Hash Table`, `String`
1831 | [Maximum Transaction Each Day](https://leetcode.com/problems/maximum-transaction-each-day) | Medium | `Database`
1830 | [Minimum Number of Operations to Make String Sorted](https://leetcode.com/problems/minimum-number-of-operations-to-make-string-sorted) | Hard | `Math`, `String`, `Combinatorics`
1829 | [Maximum XOR for Each Query](https://leetcode.com/problems/maximum-xor-for-each-query) | Medium | `Bit Manipulation`, `Array`, `Prefix Sum`
1828 | [Queries on Number of Points Inside a Circle](https://leetcode.com/problems/queries-on-number-of-points-inside-a-circle) | Medium | `Geometry`, `Array`, `Math`
1827 | [Minimum Operations to Make the Array Increasing](https://leetcode.com/problems/minimum-operations-to-make-the-array-increasing) | Easy | `Greedy`, `Array`
1826 | [Faulty Sensor](https://leetcode.com/problems/faulty-sensor) | Easy | `Array`, `Two Pointers`
1825 | [Finding MK Average](https://leetcode.com/problems/finding-mk-average) | Hard | `Design`, `Queue`, `Ordered Set`, `Heap (Priority Queue)`
1824 | [Minimum Sideway Jumps](https://leetcode.com/problems/minimum-sideway-jumps) | Medium | `Greedy`, `Array`, `Dynamic Programming`
1823 | [Find the Winner of the Circular Game](https://leetcode.com/problems/find-the-winner-of-the-circular-game) | Medium | `Recursion`, `Array`, `Math`, `Simulation`
1822 | [Sign of the Product of an Array](https://leetcode.com/problems/sign-of-the-product-of-an-array) | Easy | `Array`, `Math`
1821 | [Find Customers With Positive Revenue this Year](https://leetcode.com/problems/find-customers-with-positive-revenue-this-year) | Easy | `Database`
1820 | [Maximum Number of Accepted Invitations](https://leetcode.com/problems/maximum-number-of-accepted-invitations) | Medium | `Array`, `Backtracking`, `Matrix`
1819 | [Number of Different Subsequences GCDs](https://leetcode.com/problems/number-of-different-subsequences-gcds) | Hard | `Array`, `Math`, `Counting`, `Number Theory`
1818 | [Minimum Absolute Sum Difference](https://leetcode.com/problems/minimum-absolute-sum-difference) | Medium | `Greedy`, `Array`, `Binary Search`, `Ordered Set`
1817 | [Finding the Users Active Minutes](https://leetcode.com/problems/finding-the-users-active-minutes) | Medium | `Array`, `Hash Table`
1816 | [Truncate Sentence](https://leetcode.com/problems/truncate-sentence) | Easy | `Array`, `String`
1815 | [Maximum Number of Groups Getting Fresh Donuts](https://leetcode.com/problems/maximum-number-of-groups-getting-fresh-donuts) | Hard | `Bit Manipulation`, `Memoization`, `Array`, `Dynamic Programming`, `Bitmask`
1814 | [Count Nice Pairs in an Array](https://leetcode.com/problems/count-nice-pairs-in-an-array) | Medium | `Array`, `Hash Table`, `Math`, `Counting`
1813 | [Sentence Similarity III](https://leetcode.com/problems/sentence-similarity-iii) | Medium | `Array`, `Two Pointers`, `String`
1812 | [Determine Color of a Chessboard Square](https://leetcode.com/problems/determine-color-of-a-chessboard-square) | Easy | `Math`, `String`
1811 | [Find Interview Candidates](https://leetcode.com/problems/find-interview-candidates) | Medium | `Database`
1810 | [Minimum Path Cost in a Hidden Grid](https://leetcode.com/problems/minimum-path-cost-in-a-hidden-grid) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Interactive`, `Heap (Priority Queue)`
1809 | [Ad-Free Sessions](https://leetcode.com/problems/ad-free-sessions) | Easy | `Database`
1808 | [Maximize Number of Nice Divisors](https://leetcode.com/problems/maximize-number-of-nice-divisors) | Hard | `Recursion`, `Math`
1807 | [Evaluate the Bracket Pairs of a String](https://leetcode.com/problems/evaluate-the-bracket-pairs-of-a-string) | Medium | `Array`, `Hash Table`, `String`
1806 | [Minimum Number of Operations to Reinitialize a Permutation](https://leetcode.com/problems/minimum-number-of-operations-to-reinitialize-a-permutation) | Medium | `Array`, `Math`, `Simulation`
1805 | [Number of Different Integers in a String](https://leetcode.com/problems/number-of-different-integers-in-a-string) | Easy | `Hash Table`, `String`
1804 | [Implement Trie II (Prefix Tree)](https://leetcode.com/problems/implement-trie-ii-prefix-tree) | Medium | `Design`, `Trie`, `Hash Table`, `String`
1803 | [Count Pairs With XOR in a Range](https://leetcode.com/problems/count-pairs-with-xor-in-a-range) | Hard | `Bit Manipulation`, `Trie`, `Array`
1802 | [Maximum Value at a Given Index in a Bounded Array](https://leetcode.com/problems/maximum-value-at-a-given-index-in-a-bounded-array) | Medium | `Greedy`, `Binary Search`
1801 | [Number of Orders in the Backlog](https://leetcode.com/problems/number-of-orders-in-the-backlog) | Medium | `Array`, `Simulation`, `Heap (Priority Queue)`
1800 | [Maximum Ascending Subarray Sum](https://leetcode.com/problems/maximum-ascending-subarray-sum) | Easy | `Array`
1799 | [Maximize Score After N Operations](https://leetcode.com/problems/maximize-score-after-n-operations) | Hard | `Bit Manipulation`, `Array`, `Math`, `Dynamic Programming`, `Backtracking`, `Bitmask`, `Number Theory`
1798 | [Maximum Number of Consecutive Values You Can Make](https://leetcode.com/problems/maximum-number-of-consecutive-values-you-can-make) | Medium | `Greedy`, `Array`
1797 | [Design Authentication Manager](https://leetcode.com/problems/design-authentication-manager) | Medium | `Design`, `Hash Table`
1796 | [Second Largest Digit in a String](https://leetcode.com/problems/second-largest-digit-in-a-string) | Easy | `Hash Table`, `String`
1795 | [Rearrange Products Table](https://leetcode.com/problems/rearrange-products-table) | Easy | `Database`
1794 | [Count Pairs of Equal Substrings With Minimum Difference](https://leetcode.com/problems/count-pairs-of-equal-substrings-with-minimum-difference) | Medium | `Greedy`, `Hash Table`, `String`
1793 | [Maximum Score of a Good Subarray](https://leetcode.com/problems/maximum-score-of-a-good-subarray) | Hard | `Stack`, `Array`, `Two Pointers`, `Binary Search`, `Monotonic Stack`
1792 | [Maximum Average Pass Ratio](https://leetcode.com/problems/maximum-average-pass-ratio) | Medium | `Greedy`, `Array`, `Heap (Priority Queue)`
1791 | [Find Center of Star Graph](https://leetcode.com/problems/find-center-of-star-graph) | Easy | `Graph`
1790 | [Check if One String Swap Can Make Strings Equal](https://leetcode.com/problems/check-if-one-string-swap-can-make-strings-equal) | Easy | `Hash Table`, `String`, `Counting`
1789 | [Primary Department for Each Employee](https://leetcode.com/problems/primary-department-for-each-employee) | Easy | `Database`
1788 | [Maximize the Beauty of the Garden](https://leetcode.com/problems/maximize-the-beauty-of-the-garden) | Hard | `Greedy`, `Array`, `Prefix Sum`
1787 | [Make the XOR of All Segments Equal to Zero](https://leetcode.com/problems/make-the-xor-of-all-segments-equal-to-zero) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`
1786 | [Number of Restricted Paths From First to Last Node](https://leetcode.com/problems/number-of-restricted-paths-from-first-to-last-node) | Medium | `Graph`, `Topological Sort`, `Dynamic Programming`, `Shortest Path`, `Heap (Priority Queue)`
1785 | [Minimum Elements to Add to Form a Given Sum](https://leetcode.com/problems/minimum-elements-to-add-to-form-a-given-sum) | Medium | `Greedy`, `Array`
1784 | [Check if Binary String Has at Most One Segment of Ones](https://leetcode.com/problems/check-if-binary-string-has-at-most-one-segment-of-ones) | Easy | `String`
1783 | [Grand Slam Titles](https://leetcode.com/problems/grand-slam-titles) | Medium | `Database`
1782 | [Count Pairs Of Nodes](https://leetcode.com/problems/count-pairs-of-nodes) | Hard | `Graph`, `Two Pointers`, `Binary Search`
1781 | [Sum of Beauty of All Substrings](https://leetcode.com/problems/sum-of-beauty-of-all-substrings) | Medium | `Hash Table`, `String`, `Counting`
1780 | [Check if Number is a Sum of Powers of Three](https://leetcode.com/problems/check-if-number-is-a-sum-of-powers-of-three) | Medium | `Math`
1779 | [Find Nearest Point That Has the Same X or Y Coordinate](https://leetcode.com/problems/find-nearest-point-that-has-the-same-x-or-y-coordinate) | Easy | `Array`
1778 | [Shortest Path in a Hidden Grid](https://leetcode.com/problems/shortest-path-in-a-hidden-grid) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Interactive`
1777 | [Product's Price for Each Store](https://leetcode.com/problems/products-price-for-each-store) | Easy | `Database`
1776 | [Car Fleet II](https://leetcode.com/problems/car-fleet-ii) | Hard | `Stack`, `Array`, `Math`, `Monotonic Stack`, `Heap (Priority Queue)`
1775 | [Equal Sum Arrays With Minimum Number of Operations](https://leetcode.com/problems/equal-sum-arrays-with-minimum-number-of-operations) | Medium | `Greedy`, `Array`, `Hash Table`, `Counting`
1774 | [Closest Dessert Cost](https://leetcode.com/problems/closest-dessert-cost) | Medium | `Array`, `Dynamic Programming`, `Backtracking`
1773 | [Count Items Matching a Rule](https://leetcode.com/problems/count-items-matching-a-rule) | Easy | `Array`, `String`
1772 | [Sort Features by Popularity](https://leetcode.com/problems/sort-features-by-popularity) | Medium | `Array`, `Hash Table`, `String`, `Sorting`
1771 | [Maximize Palindrome Length From Subsequences](https://leetcode.com/problems/maximize-palindrome-length-from-subsequences) | Hard | `String`, `Dynamic Programming`
1770 | [Maximum Score from Performing Multiplication Operations](https://leetcode.com/problems/maximum-score-from-performing-multiplication-operations) | Medium | `Array`, `Dynamic Programming`
1769 | [Minimum Number of Operations to Move All Balls to Each Box](https://leetcode.com/problems/minimum-number-of-operations-to-move-all-balls-to-each-box) | Medium | `Array`, `String`
1768 | [Merge Strings Alternately](https://leetcode.com/problems/merge-strings-alternately) | Easy | `Two Pointers`, `String`
1767 | [Find the Subtasks That Did Not Execute](https://leetcode.com/problems/find-the-subtasks-that-did-not-execute) | Hard | `Database`
1766 | [Tree of Coprimes](https://leetcode.com/problems/tree-of-coprimes) | Hard | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Math`
1765 | [Map of Highest Peak](https://leetcode.com/problems/map-of-highest-peak) | Medium | `Breadth-First Search`, `Array`, `Matrix`
1764 | [Form Array by Concatenating Subarrays of Another Array](https://leetcode.com/problems/form-array-by-concatenating-subarrays-of-another-array) | Medium | `Greedy`, `Array`, `String Matching`
1763 | [Longest Nice Substring](https://leetcode.com/problems/longest-nice-substring) | Easy | `Bit Manipulation`, `Hash Table`, `String`, `Sliding Window`
1762 | [Buildings With an Ocean View](https://leetcode.com/problems/buildings-with-an-ocean-view) | Medium | `Stack`, `Array`, `Monotonic Stack`
1761 | [Minimum Degree of a Connected Trio in a Graph](https://leetcode.com/problems/minimum-degree-of-a-connected-trio-in-a-graph) | Hard | `Graph`
1760 | [Minimum Limit of Balls in a Bag](https://leetcode.com/problems/minimum-limit-of-balls-in-a-bag) | Medium | `Array`, `Binary Search`
1759 | [Count Number of Homogenous Substrings](https://leetcode.com/problems/count-number-of-homogenous-substrings) | Medium | `Math`, `String`
1758 | [Minimum Changes To Make Alternating Binary String](https://leetcode.com/problems/minimum-changes-to-make-alternating-binary-string) | Easy | `String`
1757 | [Recyclable and Low Fat Products](https://leetcode.com/problems/recyclable-and-low-fat-products) | Easy | `Database`
1756 | [Design Most Recently Used Queue](https://leetcode.com/problems/design-most-recently-used-queue) | Medium | `Stack`, `Design`, `Binary Indexed Tree`, `Array`, `Hash Table`, `Ordered Set`
1755 | [Closest Subsequence Sum](https://leetcode.com/problems/closest-subsequence-sum) | Hard | `Bit Manipulation`, `Array`, `Two Pointers`, `Dynamic Programming`, `Bitmask`
1754 | [Largest Merge Of Two Strings](https://leetcode.com/problems/largest-merge-of-two-strings) | Medium | `Greedy`, `Two Pointers`, `String`
1753 | [Maximum Score From Removing Stones](https://leetcode.com/problems/maximum-score-from-removing-stones) | Medium | `Greedy`, `Math`, `Heap (Priority Queue)`
1752 | [Check if Array Is Sorted and Rotated](https://leetcode.com/problems/check-if-array-is-sorted-and-rotated) | Easy | `Array`
1751 | [Maximum Number of Events That Can Be Attended II](https://leetcode.com/problems/maximum-number-of-events-that-can-be-attended-ii) | Hard | `Array`, `Binary Search`, `Dynamic Programming`
1750 | [Minimum Length of String After Deleting Similar Ends](https://leetcode.com/problems/minimum-length-of-string-after-deleting-similar-ends) | Medium | `Two Pointers`, `String`
1749 | [Maximum Absolute Sum of Any Subarray](https://leetcode.com/problems/maximum-absolute-sum-of-any-subarray) | Medium | `Array`, `Dynamic Programming`
1748 | [Sum of Unique Elements](https://leetcode.com/problems/sum-of-unique-elements) | Easy | `Array`, `Hash Table`, `Counting`
1747 | [Leetflex Banned Accounts](https://leetcode.com/problems/leetflex-banned-accounts) | Medium | `Database`
1746 | [Maximum Subarray Sum After One Operation](https://leetcode.com/problems/maximum-subarray-sum-after-one-operation) | Medium | `Array`, `Dynamic Programming`
1745 | [Palindrome Partitioning IV](https://leetcode.com/problems/palindrome-partitioning-iv) | Hard | `String`, `Dynamic Programming`
1744 | [Can You Eat Your Favorite Candy on Your Favorite Day?](https://leetcode.com/problems/can-you-eat-your-favorite-candy-on-your-favorite-day) | Medium | `Array`, `Prefix Sum`
1743 | [Restore the Array From Adjacent Pairs](https://leetcode.com/problems/restore-the-array-from-adjacent-pairs) | Medium | `Array`, `Hash Table`
1742 | [Maximum Number of Balls in a Box](https://leetcode.com/problems/maximum-number-of-balls-in-a-box) | Easy | `Hash Table`, `Math`, `Counting`
1741 | [Find Total Time Spent by Each Employee](https://leetcode.com/problems/find-total-time-spent-by-each-employee) | Easy | `Database`
1740 | [Find Distance in a Binary Tree](https://leetcode.com/problems/find-distance-in-a-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`, `Binary Tree`
1739 | [Building Boxes](https://leetcode.com/problems/building-boxes) | Hard | `Greedy`, `Math`, `Binary Search`
1738 | [Find Kth Largest XOR Coordinate Value](https://leetcode.com/problems/find-kth-largest-xor-coordinate-value) | Medium | `Bit Manipulation`, `Array`, `Divide and Conquer`, `Matrix`, `Prefix Sum`, `Quickselect`, `Heap (Priority Queue)`
1737 | [Change Minimum Characters to Satisfy One of Three Conditions](https://leetcode.com/problems/change-minimum-characters-to-satisfy-one-of-three-conditions) | Medium | `Hash Table`, `String`, `Counting`, `Prefix Sum`
1736 | [Latest Time by Replacing Hidden Digits](https://leetcode.com/problems/latest-time-by-replacing-hidden-digits) | Easy | `String`
1735 | [Count Ways to Make Array With Product](https://leetcode.com/problems/count-ways-to-make-array-with-product) | Hard | `Array`, `Math`, `Dynamic Programming`
1734 | [Decode XORed Permutation](https://leetcode.com/problems/decode-xored-permutation) | Medium | `Bit Manipulation`, `Array`
1733 | [Minimum Number of People to Teach](https://leetcode.com/problems/minimum-number-of-people-to-teach) | Medium | `Greedy`, `Array`
1732 | [Find the Highest Altitude](https://leetcode.com/problems/find-the-highest-altitude) | Easy | `Array`, `Prefix Sum`
1731 | [The Number of Employees Which Report to Each Employee](https://leetcode.com/problems/the-number-of-employees-which-report-to-each-employee) | Easy | `Database`
1730 | [Shortest Path to Get Food](https://leetcode.com/problems/shortest-path-to-get-food) | Medium | `Breadth-First Search`, `Array`, `Matrix`
1729 | [Find Followers Count](https://leetcode.com/problems/find-followers-count) | Easy | `Database`
1728 | [Cat and Mouse II](https://leetcode.com/problems/cat-and-mouse-ii) | Hard | `Breadth-First Search`, `Graph`, `Memoization`, `Math`, `Dynamic Programming`, `Game Theory`
1727 | [Largest Submatrix With Rearrangements](https://leetcode.com/problems/largest-submatrix-with-rearrangements) | Medium | `Greedy`, `Array`, `Matrix`, `Sorting`
1726 | [Tuple with Same Product](https://leetcode.com/problems/tuple-with-same-product) | Medium | `Array`, `Hash Table`
1725 | [Number Of Rectangles That Can Form The Largest Square](https://leetcode.com/problems/number-of-rectangles-that-can-form-the-largest-square) | Easy | `Array`
1724 | [Checking Existence of Edge Length Limited Paths II](https://leetcode.com/problems/checking-existence-of-edge-length-limited-paths-ii) | Hard | `Union Find`, `Graph`, `Minimum Spanning Tree`
1723 | [Find Minimum Time to Finish All Jobs](https://leetcode.com/problems/find-minimum-time-to-finish-all-jobs) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
1722 | [Minimize Hamming Distance After Swap Operations](https://leetcode.com/problems/minimize-hamming-distance-after-swap-operations) | Medium | `Depth-First Search`, `Union Find`, `Array`
1721 | [Swapping Nodes in a Linked List](https://leetcode.com/problems/swapping-nodes-in-a-linked-list) | Medium | `Linked List`, `Two Pointers`
1720 | [Decode XORed Array](https://leetcode.com/problems/decode-xored-array) | Easy | `Bit Manipulation`, `Array`
1719 | [Number Of Ways To Reconstruct A Tree](https://leetcode.com/problems/number-of-ways-to-reconstruct-a-tree) | Hard | `Tree`, `Graph`, `Topological Sort`
1718 | [Construct the Lexicographically Largest Valid Sequence](https://leetcode.com/problems/construct-the-lexicographically-largest-valid-sequence) | Medium | `Array`, `Backtracking`
1717 | [Maximum Score From Removing Substrings](https://leetcode.com/problems/maximum-score-from-removing-substrings) | Medium | `Stack`, `Greedy`, `String`
1716 | [Calculate Money in Leetcode Bank](https://leetcode.com/problems/calculate-money-in-leetcode-bank) | Easy | `Math`
1715 | [Count Apples and Oranges](https://leetcode.com/problems/count-apples-and-oranges) | Medium | `Database`
1714 | [Sum Of Special Evenly-Spaced Elements In Array](https://leetcode.com/problems/sum-of-special-evenly-spaced-elements-in-array) | Hard | `Array`, `Dynamic Programming`
1713 | [Minimum Operations to Make a Subsequence](https://leetcode.com/problems/minimum-operations-to-make-a-subsequence) | Hard | `Greedy`, `Array`, `Hash Table`, `Binary Search`
1712 | [Ways to Split Array Into Three Subarrays](https://leetcode.com/problems/ways-to-split-array-into-three-subarrays) | Medium | `Array`, `Two Pointers`, `Binary Search`, `Prefix Sum`
1711 | [Count Good Meals](https://leetcode.com/problems/count-good-meals) | Medium | `Array`, `Hash Table`
1710 | [Maximum Units on a Truck](https://leetcode.com/problems/maximum-units-on-a-truck) | Easy | `Greedy`, `Array`, `Sorting`
1709 | [Biggest Window Between Visits](https://leetcode.com/problems/biggest-window-between-visits) | Medium | `Database`
1708 | [Largest Subarray Length K](https://leetcode.com/problems/largest-subarray-length-k) | Easy | `Greedy`, `Array`
1707 | [Maximum XOR With an Element From Array](https://leetcode.com/problems/maximum-xor-with-an-element-from-array) | Hard | `Bit Manipulation`, `Trie`, `Array`
1706 | [Where Will the Ball Fall](https://leetcode.com/problems/where-will-the-ball-fall) | Medium | `Depth-First Search`, `Array`, `Dynamic Programming`, `Matrix`, `Simulation`
1705 | [Maximum Number of Eaten Apples](https://leetcode.com/problems/maximum-number-of-eaten-apples) | Medium | `Greedy`, `Array`, `Heap (Priority Queue)`
1704 | [Determine if String Halves Are Alike](https://leetcode.com/problems/determine-if-string-halves-are-alike) | Easy | `String`, `Counting`
1703 | [Minimum Adjacent Swaps for K Consecutive Ones](https://leetcode.com/problems/minimum-adjacent-swaps-for-k-consecutive-ones) | Hard | `Greedy`, `Array`, `Prefix Sum`, `Sliding Window`
1702 | [Maximum Binary String After Change](https://leetcode.com/problems/maximum-binary-string-after-change) | Medium | `Greedy`, `String`
1701 | [Average Waiting Time](https://leetcode.com/problems/average-waiting-time) | Medium | `Array`, `Simulation`
1700 | [Number of Students Unable to Eat Lunch](https://leetcode.com/problems/number-of-students-unable-to-eat-lunch) | Easy | `Stack`, `Queue`, `Array`, `Simulation`
1699 | [Number of Calls Between Two Persons](https://leetcode.com/problems/number-of-calls-between-two-persons) | Medium | `Database`
1698 | [Number of Distinct Substrings in a String](https://leetcode.com/problems/number-of-distinct-substrings-in-a-string) | Medium | `Trie`, `String`, `Suffix Array`, `Hash Function`, `Rolling Hash`
1697 | [Checking Existence of Edge Length Limited Paths](https://leetcode.com/problems/checking-existence-of-edge-length-limited-paths) | Hard | `Union Find`, `Graph`, `Array`, `Sorting`
1696 | [Jump Game VI](https://leetcode.com/problems/jump-game-vi) | Medium | `Queue`, `Array`, `Dynamic Programming`, `Sliding Window`, `Monotonic Queue`, `Heap (Priority Queue)`
1695 | [Maximum Erasure Value](https://leetcode.com/problems/maximum-erasure-value) | Medium | `Array`, `Hash Table`, `Sliding Window`
1694 | [Reformat Phone Number](https://leetcode.com/problems/reformat-phone-number) | Easy | `String`
1693 | [Daily Leads and Partners](https://leetcode.com/problems/daily-leads-and-partners) | Easy | `Database`
1692 | [Count Ways to Distribute Candies](https://leetcode.com/problems/count-ways-to-distribute-candies) | Hard | `Dynamic Programming`
1691 | [Maximum Height by Stacking Cuboids ](https://leetcode.com/problems/maximum-height-by-stacking-cuboids) | Hard | `Array`, `Dynamic Programming`, `Sorting`
1690 | [Stone Game VII](https://leetcode.com/problems/stone-game-vii) | Medium | `Array`, `Math`, `Dynamic Programming`, `Game Theory`
1689 | [Partitioning Into Minimum Number Of Deci-Binary Numbers](https://leetcode.com/problems/partitioning-into-minimum-number-of-deci-binary-numbers) | Medium | `Greedy`, `String`
1688 | [Count of Matches in Tournament](https://leetcode.com/problems/count-of-matches-in-tournament) | Easy | `Math`, `Simulation`
1687 | [Delivering Boxes from Storage to Ports](https://leetcode.com/problems/delivering-boxes-from-storage-to-ports) | Hard | `Segment Tree`, `Queue`, `Array`, `Dynamic Programming`, `Monotonic Queue`, `Heap (Priority Queue)`
1686 | [Stone Game VI](https://leetcode.com/problems/stone-game-vi) | Medium | `Greedy`, `Array`, `Math`, `Game Theory`, `Sorting`, `Heap (Priority Queue)`
1685 | [Sum of Absolute Differences in a Sorted Array](https://leetcode.com/problems/sum-of-absolute-differences-in-a-sorted-array) | Medium | `Array`, `Math`, `Prefix Sum`
1684 | [Count the Number of Consistent Strings](https://leetcode.com/problems/count-the-number-of-consistent-strings) | Easy | `Bit Manipulation`, `Array`, `Hash Table`, `String`
1683 | [Invalid Tweets](https://leetcode.com/problems/invalid-tweets) | Easy | `Database`
1682 | [Longest Palindromic Subsequence II](https://leetcode.com/problems/longest-palindromic-subsequence-ii) | Medium | `String`, `Dynamic Programming`
1681 | [Minimum Incompatibility](https://leetcode.com/problems/minimum-incompatibility) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Bitmask`
1680 | [Concatenation of Consecutive Binary Numbers](https://leetcode.com/problems/concatenation-of-consecutive-binary-numbers) | Medium | `Bit Manipulation`, `Math`, `Simulation`
1679 | [Max Number of K-Sum Pairs](https://leetcode.com/problems/max-number-of-k-sum-pairs) | Medium | `Array`, `Hash Table`, `Two Pointers`, `Sorting`
1678 | [Goal Parser Interpretation](https://leetcode.com/problems/goal-parser-interpretation) | Easy | `String`
1677 | [Product's Worth Over Invoices](https://leetcode.com/problems/products-worth-over-invoices) | Easy | `Database`
1676 | [Lowest Common Ancestor of a Binary Tree IV](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree-iv) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1675 | [Minimize Deviation in Array](https://leetcode.com/problems/minimize-deviation-in-array) | Hard | `Greedy`, `Array`, `Ordered Set`, `Heap (Priority Queue)`
1674 | [Minimum Moves to Make Array Complementary](https://leetcode.com/problems/minimum-moves-to-make-array-complementary) | Medium | `Array`, `Hash Table`, `Prefix Sum`
1673 | [Find the Most Competitive Subsequence](https://leetcode.com/problems/find-the-most-competitive-subsequence) | Medium | `Stack`, `Greedy`, `Array`, `Monotonic Stack`
1672 | [Richest Customer Wealth](https://leetcode.com/problems/richest-customer-wealth) | Easy | `Array`, `Matrix`
1671 | [Minimum Number of Removals to Make Mountain Array](https://leetcode.com/problems/minimum-number-of-removals-to-make-mountain-array) | Hard | `Greedy`, `Array`, `Binary Search`, `Dynamic Programming`
1670 | [Design Front Middle Back Queue](https://leetcode.com/problems/design-front-middle-back-queue) | Medium | `Design`, `Queue`, `Array`, `Linked List`, `Data Stream`
1669 | [Merge In Between Linked Lists](https://leetcode.com/problems/merge-in-between-linked-lists) | Medium | `Linked List`
1668 | [Maximum Repeating Substring](https://leetcode.com/problems/maximum-repeating-substring) | Easy | `String`, `String Matching`
1667 | [Fix Names in a Table](https://leetcode.com/problems/fix-names-in-a-table) | Easy | `Database`
1666 | [Change the Root of a Binary Tree](https://leetcode.com/problems/change-the-root-of-a-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1664 | [Ways to Make a Fair Array](https://leetcode.com/problems/ways-to-make-a-fair-array) | Medium | `Array`, `Dynamic Programming`
1663 | [Smallest String With A Given Numeric Value](https://leetcode.com/problems/smallest-string-with-a-given-numeric-value) | Medium | `Greedy`, `String`
1662 | [Check If Two String Arrays are Equivalent](https://leetcode.com/problems/check-if-two-string-arrays-are-equivalent) | Easy | `Array`, `String`
1661 | [Average Time of Process per Machine](https://leetcode.com/problems/average-time-of-process-per-machine) | Easy | `Database`
1660 | [Correct a Binary Tree](https://leetcode.com/problems/correct-a-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`, `Binary Tree`
1659 | [Maximize Grid Happiness](https://leetcode.com/problems/maximize-grid-happiness) | Hard | `Bit Manipulation`, `Memoization`, `Dynamic Programming`, `Bitmask`
1658 | [Minimum Operations to Reduce X to Zero](https://leetcode.com/problems/minimum-operations-to-reduce-x-to-zero) | Medium | `Array`, `Hash Table`, `Two Pointers`, `Binary Search`, `Prefix Sum`
1657 | [Determine if Two Strings Are Close](https://leetcode.com/problems/determine-if-two-strings-are-close) | Medium | `Hash Table`, `String`, `Sorting`
1656 | [Design an Ordered Stream](https://leetcode.com/problems/design-an-ordered-stream) | Easy | `Design`, `Array`, `Hash Table`, `Data Stream`
1655 | [Distribute Repeating Integers](https://leetcode.com/problems/distribute-repeating-integers) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
1654 | [Minimum Jumps to Reach Home](https://leetcode.com/problems/minimum-jumps-to-reach-home) | Medium | `Breadth-First Search`, `Array`, `Dynamic Programming`
1653 | [Minimum Deletions to Make String Balanced](https://leetcode.com/problems/minimum-deletions-to-make-string-balanced) | Medium | `Stack`, `String`, `Dynamic Programming`
1652 | [Defuse the Bomb](https://leetcode.com/problems/defuse-the-bomb) | Easy | `Array`
1651 | [Hopper Company Queries III](https://leetcode.com/problems/hopper-company-queries-iii) | Hard | `Database`
1650 | [Lowest Common Ancestor of a Binary Tree III](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree-iii) | Medium | `Tree`, `Hash Table`, `Binary Tree`
1649 | [Create Sorted Array through Instructions](https://leetcode.com/problems/create-sorted-array-through-instructions) | Hard | `Binary Indexed Tree`, `Segment Tree`, `Array`, `Binary Search`, `Divide and Conquer`, `Ordered Set`, `Merge Sort`
1648 | [Sell Diminishing-Valued Colored Balls](https://leetcode.com/problems/sell-diminishing-valued-colored-balls) | Medium | `Greedy`, `Array`, `Math`, `Binary Search`, `Sorting`, `Heap (Priority Queue)`
1647 | [Minimum Deletions to Make Character Frequencies Unique](https://leetcode.com/problems/minimum-deletions-to-make-character-frequencies-unique) | Medium | `Greedy`, `String`, `Sorting`
1646 | [Get Maximum in Generated Array](https://leetcode.com/problems/get-maximum-in-generated-array) | Easy | `Array`, `Dynamic Programming`, `Simulation`
1645 | [Hopper Company Queries II](https://leetcode.com/problems/hopper-company-queries-ii) | Hard | `Database`
1644 | [Lowest Common Ancestor of a Binary Tree II](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree-ii) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1643 | [Kth Smallest Instructions](https://leetcode.com/problems/kth-smallest-instructions) | Hard | `Array`, `Math`, `Dynamic Programming`, `Combinatorics`
1642 | [Furthest Building You Can Reach](https://leetcode.com/problems/furthest-building-you-can-reach) | Medium | `Greedy`, `Array`, `Heap (Priority Queue)`
1641 | [Count Sorted Vowel Strings](https://leetcode.com/problems/count-sorted-vowel-strings) | Medium | `Dynamic Programming`
1640 | [Check Array Formation Through Concatenation](https://leetcode.com/problems/check-array-formation-through-concatenation) | Easy | `Array`, `Hash Table`
1639 | [Number of Ways to Form a Target String Given a Dictionary](https://leetcode.com/problems/number-of-ways-to-form-a-target-string-given-a-dictionary) | Hard | `Array`, `String`, `Dynamic Programming`
1638 | [Count Substrings That Differ by One Character](https://leetcode.com/problems/count-substrings-that-differ-by-one-character) | Medium | `Hash Table`, `String`, `Dynamic Programming`
1637 | [Widest Vertical Area Between Two Points Containing No Points](https://leetcode.com/problems/widest-vertical-area-between-two-points-containing-no-points) | Medium | `Array`, `Sorting`
1636 | [Sort Array by Increasing Frequency](https://leetcode.com/problems/sort-array-by-increasing-frequency) | Easy | `Array`, `Hash Table`, `Sorting`
1635 | [Hopper Company Queries I](https://leetcode.com/problems/hopper-company-queries-i) | Hard | `Database`
1634 | [Add Two Polynomials Represented as Linked Lists](https://leetcode.com/problems/add-two-polynomials-represented-as-linked-lists) | Medium | `Linked List`, `Math`, `Two Pointers`
1633 | [Percentage of Users Attended a Contest](https://leetcode.com/problems/percentage-of-users-attended-a-contest) | Easy | `Database`
1632 | [Rank Transform of a Matrix](https://leetcode.com/problems/rank-transform-of-a-matrix) | Hard | `Greedy`, `Union Find`, `Graph`, `Topological Sort`, `Array`, `Matrix`
1631 | [Path With Minimum Effort](https://leetcode.com/problems/path-with-minimum-effort) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Binary Search`, `Matrix`, `Heap (Priority Queue)`
1630 | [Arithmetic Subarrays](https://leetcode.com/problems/arithmetic-subarrays) | Medium | `Array`, `Sorting`
1629 | [Slowest Key](https://leetcode.com/problems/slowest-key) | Easy | `Array`, `String`
1628 | [Design an Expression Tree With Evaluate Function](https://leetcode.com/problems/design-an-expression-tree-with-evaluate-function) | Medium | `Stack`, `Tree`, `Design`, `Math`, `Binary Tree`
1627 | [Graph Connectivity With Threshold](https://leetcode.com/problems/graph-connectivity-with-threshold) | Hard | `Union Find`, `Array`, `Math`
1626 | [Best Team With No Conflicts](https://leetcode.com/problems/best-team-with-no-conflicts) | Medium | `Array`, `Dynamic Programming`, `Sorting`
1625 | [Lexicographically Smallest String After Applying Operations](https://leetcode.com/problems/lexicographically-smallest-string-after-applying-operations) | Medium | `Breadth-First Search`, `String`
1624 | [Largest Substring Between Two Equal Characters](https://leetcode.com/problems/largest-substring-between-two-equal-characters) | Easy | `Hash Table`, `String`
1623 | [All Valid Triplets That Can Represent a Country](https://leetcode.com/problems/all-valid-triplets-that-can-represent-a-country) | Easy | `Database`
1622 | [Fancy Sequence](https://leetcode.com/problems/fancy-sequence) | Hard | `Design`, `Segment Tree`, `Math`
1621 | [Number of Sets of K Non-Overlapping Line Segments](https://leetcode.com/problems/number-of-sets-of-k-non-overlapping-line-segments) | Medium | `Math`, `Dynamic Programming`
1620 | [Coordinate With Maximum Network Quality](https://leetcode.com/problems/coordinate-with-maximum-network-quality) | Medium | `Array`, `Enumeration`
1619 | [Mean of Array After Removing Some Elements](https://leetcode.com/problems/mean-of-array-after-removing-some-elements) | Easy | `Array`, `Sorting`
1618 | [Maximum Font to Fit a Sentence in a Screen](https://leetcode.com/problems/maximum-font-to-fit-a-sentence-in-a-screen) | Medium | `Array`, `String`, `Binary Search`, `Interactive`
1617 | [Count Subtrees With Max Distance Between Cities](https://leetcode.com/problems/count-subtrees-with-max-distance-between-cities) | Hard | `Bit Manipulation`, `Tree`, `Dynamic Programming`, `Bitmask`, `Enumeration`
1616 | [Split Two Strings to Make Palindrome](https://leetcode.com/problems/split-two-strings-to-make-palindrome) | Medium | `Greedy`, `Two Pointers`, `String`
1615 | [Maximal Network Rank](https://leetcode.com/problems/maximal-network-rank) | Medium | `Graph`
1614 | [Maximum Nesting Depth of the Parentheses](https://leetcode.com/problems/maximum-nesting-depth-of-the-parentheses) | Easy | `Stack`, `String`
1613 | [Find the Missing IDs](https://leetcode.com/problems/find-the-missing-ids) | Medium | `Database`
1612 | [Check If Two Expression Trees are Equivalent](https://leetcode.com/problems/check-if-two-expression-trees-are-equivalent) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1611 | [Minimum One Bit Operations to Make Integers Zero](https://leetcode.com/problems/minimum-one-bit-operations-to-make-integers-zero) | Hard | `Bit Manipulation`, `Memoization`, `Dynamic Programming`
1610 | [Maximum Number of Visible Points](https://leetcode.com/problems/maximum-number-of-visible-points) | Hard | `Geometry`, `Array`, `Math`, `Sorting`, `Sliding Window`
1609 | [Even Odd Tree](https://leetcode.com/problems/even-odd-tree) | Medium | `Tree`, `Breadth-First Search`, `Binary Tree`
1608 | [Special Array With X Elements Greater Than or Equal X](https://leetcode.com/problems/special-array-with-x-elements-greater-than-or-equal-x) | Easy | `Array`, `Binary Search`, `Sorting`
1607 | [Sellers With No Sales](https://leetcode.com/problems/sellers-with-no-sales) | Easy | `Database`
1606 | [Find Servers That Handled Most Number of Requests](https://leetcode.com/problems/find-servers-that-handled-most-number-of-requests) | Hard | `Greedy`, `Array`, `Ordered Set`, `Heap (Priority Queue)`
1605 | [Find Valid Matrix Given Row and Column Sums](https://leetcode.com/problems/find-valid-matrix-given-row-and-column-sums) | Medium | `Greedy`, `Array`, `Matrix`
1604 | [Alert Using Same Key-Card Three or More Times in a One Hour Period](https://leetcode.com/problems/alert-using-same-key-card-three-or-more-times-in-a-one-hour-period) | Medium | `Array`, `Hash Table`, `String`, `Sorting`
1603 | [Design Parking System](https://leetcode.com/problems/design-parking-system) | Easy | `Design`, `Counting`, `Simulation`
1602 | [Find Nearest Right Node in Binary Tree](https://leetcode.com/problems/find-nearest-right-node-in-binary-tree) | Medium | `Tree`, `Breadth-First Search`, `Binary Tree`
1601 | [Maximum Number of Achievable Transfer Requests](https://leetcode.com/problems/maximum-number-of-achievable-transfer-requests) | Hard | `Bit Manipulation`, `Enumeration`
1600 | [Throne Inheritance](https://leetcode.com/problems/throne-inheritance) | Medium | `Tree`, `Depth-First Search`, `Design`, `Hash Table`
1599 | [Maximum Profit of Operating a Centennial Wheel](https://leetcode.com/problems/maximum-profit-of-operating-a-centennial-wheel) | Medium | `Array`, `Simulation`
1598 | [Crawler Log Folder](https://leetcode.com/problems/crawler-log-folder) | Easy | `Stack`, `Array`, `String`
1597 | [Build Binary Expression Tree From Infix Expression](https://leetcode.com/problems/build-binary-expression-tree-from-infix-expression) | Hard | `Stack`, `Tree`, `String`, `Binary Tree`
1596 | [The Most Frequently Ordered Products for Each Customer](https://leetcode.com/problems/the-most-frequently-ordered-products-for-each-customer) | Medium | `Database`
1595 | [Minimum Cost to Connect Two Groups of Points](https://leetcode.com/problems/minimum-cost-to-connect-two-groups-of-points) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Bitmask`, `Matrix`
1594 | [Maximum Non Negative Product in a Matrix](https://leetcode.com/problems/maximum-non-negative-product-in-a-matrix) | Medium | `Array`, `Dynamic Programming`, `Matrix`
1593 | [Split a String Into the Max Number of Unique Substrings](https://leetcode.com/problems/split-a-string-into-the-max-number-of-unique-substrings) | Medium | `Hash Table`, `String`, `Backtracking`
1592 | [Rearrange Spaces Between Words](https://leetcode.com/problems/rearrange-spaces-between-words) | Easy | `String`
1591 | [Strange Printer II](https://leetcode.com/problems/strange-printer-ii) | Hard | `Graph`, `Topological Sort`, `Array`, `Matrix`
1590 | [Make Sum Divisible by P](https://leetcode.com/problems/make-sum-divisible-by-p) | Medium | `Array`, `Hash Table`, `Prefix Sum`
1589 | [Maximum Sum Obtained of Any Permutation](https://leetcode.com/problems/maximum-sum-obtained-of-any-permutation) | Medium | `Greedy`, `Array`, `Prefix Sum`, `Sorting`
1588 | [Sum of All Odd Length Subarrays](https://leetcode.com/problems/sum-of-all-odd-length-subarrays) | Easy | `Array`, `Math`, `Prefix Sum`
1587 | [Bank Account Summary II](https://leetcode.com/problems/bank-account-summary-ii) | Easy | `Database`
1586 | [Binary Search Tree Iterator II](https://leetcode.com/problems/binary-search-tree-iterator-ii) | Medium | `Stack`, `Tree`, `Design`, `Binary Search Tree`, `Binary Tree`, `Iterator`
1585 | [Check If String Is Transformable With Substring Sort Operations](https://leetcode.com/problems/check-if-string-is-transformable-with-substring-sort-operations) | Hard | `Greedy`, `String`, `Sorting`
1584 | [Min Cost to Connect All Points](https://leetcode.com/problems/min-cost-to-connect-all-points) | Medium | `Union Find`, `Array`, `Minimum Spanning Tree`
1583 | [Count Unhappy Friends](https://leetcode.com/problems/count-unhappy-friends) | Medium | `Array`, `Simulation`
1582 | [Special Positions in a Binary Matrix](https://leetcode.com/problems/special-positions-in-a-binary-matrix) | Easy | `Array`, `Matrix`
1581 | [Customer Who Visited but Did Not Make Any Transactions](https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions) | Easy | `Database`
1580 | [Put Boxes Into the Warehouse II](https://leetcode.com/problems/put-boxes-into-the-warehouse-ii) | Medium | `Greedy`, `Array`, `Sorting`
1579 | [Remove Max Number of Edges to Keep Graph Fully Traversable](https://leetcode.com/problems/remove-max-number-of-edges-to-keep-graph-fully-traversable) | Hard | `Union Find`, `Graph`
1578 | [Minimum Deletion Cost to Avoid Repeating Letters](https://leetcode.com/problems/minimum-deletion-cost-to-avoid-repeating-letters) | Medium | `Greedy`, `Array`, `String`, `Dynamic Programming`
1577 | [Number of Ways Where Square of Number Is Equal to Product of Two Numbers](https://leetcode.com/problems/number-of-ways-where-square-of-number-is-equal-to-product-of-two-numbers) | Medium | `Array`, `Hash Table`, `Math`, `Two Pointers`
1576 | [Replace All ?'s to Avoid Consecutive Repeating Characters](https://leetcode.com/problems/replace-all-s-to-avoid-consecutive-repeating-characters) | Easy | `String`
1575 | [Count All Possible Routes](https://leetcode.com/problems/count-all-possible-routes) | Hard | `Memoization`, `Array`, `Dynamic Programming`
1574 | [Shortest Subarray to be Removed to Make Array Sorted](https://leetcode.com/problems/shortest-subarray-to-be-removed-to-make-array-sorted) | Medium | `Stack`, `Array`, `Two Pointers`, `Binary Search`, `Monotonic Stack`
1573 | [Number of Ways to Split a String](https://leetcode.com/problems/number-of-ways-to-split-a-string) | Medium | `Math`, `String`
1572 | [Matrix Diagonal Sum](https://leetcode.com/problems/matrix-diagonal-sum) | Easy | `Array`, `Matrix`
1571 | [Warehouse Manager](https://leetcode.com/problems/warehouse-manager) | Easy | `Database`
1570 | [Dot Product of Two Sparse Vectors](https://leetcode.com/problems/dot-product-of-two-sparse-vectors) | Medium | `Design`, `Array`, `Hash Table`, `Two Pointers`
1569 | [Number of Ways to Reorder Array to Get Same BST](https://leetcode.com/problems/number-of-ways-to-reorder-array-to-get-same-bst) | Hard | `Tree`, `Union Find`, `Binary Search Tree`, `Memoization`, `Array`, `Math`, `Divide and Conquer`, `Dynamic Programming`, `Binary Tree`, `Combinatorics`
1568 | [Minimum Number of Days to Disconnect Island](https://leetcode.com/problems/minimum-number-of-days-to-disconnect-island) | Hard | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`, `Strongly Connected Component`
1567 | [Maximum Length of Subarray With Positive Product](https://leetcode.com/problems/maximum-length-of-subarray-with-positive-product) | Medium | `Greedy`, `Array`, `Dynamic Programming`
1566 | [Detect Pattern of Length M Repeated K or More Times](https://leetcode.com/problems/detect-pattern-of-length-m-repeated-k-or-more-times) | Easy | `Array`, `Enumeration`
1565 | [Unique Orders and Customers Per Month](https://leetcode.com/problems/unique-orders-and-customers-per-month) | Easy | `Database`
1564 | [Put Boxes Into the Warehouse I](https://leetcode.com/problems/put-boxes-into-the-warehouse-i) | Medium | `Greedy`, `Array`, `Sorting`
1563 | [Stone Game V](https://leetcode.com/problems/stone-game-v) | Hard | `Array`, `Math`, `Dynamic Programming`, `Game Theory`
1562 | [Find Latest Group of Size M](https://leetcode.com/problems/find-latest-group-of-size-m) | Medium | `Array`, `Binary Search`, `Simulation`
1561 | [Maximum Number of Coins You Can Get](https://leetcode.com/problems/maximum-number-of-coins-you-can-get) | Medium | `Greedy`, `Array`, `Math`, `Game Theory`, `Sorting`
1560 | [Most Visited Sector in a Circular Track](https://leetcode.com/problems/most-visited-sector-in-a-circular-track) | Easy | `Array`, `Simulation`
1559 | [Detect Cycles in 2D Grid](https://leetcode.com/problems/detect-cycles-in-2d-grid) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
1558 | [Minimum Numbers of Function Calls to Make Target Array](https://leetcode.com/problems/minimum-numbers-of-function-calls-to-make-target-array) | Medium | `Greedy`, `Array`
1557 | [Minimum Number of Vertices to Reach All Nodes](https://leetcode.com/problems/minimum-number-of-vertices-to-reach-all-nodes) | Medium | `Graph`
1556 | [Thousand Separator](https://leetcode.com/problems/thousand-separator) | Easy | `String`
1555 | [Bank Account Summary](https://leetcode.com/problems/bank-account-summary) | Medium | `Database`
1554 | [Strings Differ by One Character](https://leetcode.com/problems/strings-differ-by-one-character) | Medium | `Hash Table`, `String`, `Hash Function`, `Rolling Hash`
1553 | [Minimum Number of Days to Eat N Oranges](https://leetcode.com/problems/minimum-number-of-days-to-eat-n-oranges) | Hard | `Memoization`, `Dynamic Programming`
1552 | [Magnetic Force Between Two Balls](https://leetcode.com/problems/magnetic-force-between-two-balls) | Medium | `Array`, `Binary Search`, `Sorting`
1551 | [Minimum Operations to Make Array Equal](https://leetcode.com/problems/minimum-operations-to-make-array-equal) | Medium | `Math`
1550 | [Three Consecutive Odds](https://leetcode.com/problems/three-consecutive-odds) | Easy | `Array`
1549 | [The Most Recent Orders for Each Product](https://leetcode.com/problems/the-most-recent-orders-for-each-product) | Medium | `Database`
1548 | [The Most Similar Path in a Graph](https://leetcode.com/problems/the-most-similar-path-in-a-graph) | Hard | `Graph`, `Dynamic Programming`
1547 | [Minimum Cost to Cut a Stick](https://leetcode.com/problems/minimum-cost-to-cut-a-stick) | Hard | `Array`, `Dynamic Programming`
1546 | [Maximum Number of Non-Overlapping Subarrays With Sum Equals Target](https://leetcode.com/problems/maximum-number-of-non-overlapping-subarrays-with-sum-equals-target) | Medium | `Greedy`, `Array`, `Hash Table`, `Prefix Sum`
1545 | [Find Kth Bit in Nth Binary String](https://leetcode.com/problems/find-kth-bit-in-nth-binary-string) | Medium | `Recursion`, `String`
1544 | [Make The String Great](https://leetcode.com/problems/make-the-string-great) | Easy | `Stack`, `String`
1543 | [Fix Product Name Format](https://leetcode.com/problems/fix-product-name-format) | Easy | `Database`
1542 | [Find Longest Awesome Substring](https://leetcode.com/problems/find-longest-awesome-substring) | Hard | `Bit Manipulation`, `Hash Table`, `String`
1541 | [Minimum Insertions to Balance a Parentheses String](https://leetcode.com/problems/minimum-insertions-to-balance-a-parentheses-string) | Medium | `Stack`, `Greedy`, `String`
1540 | [Can Convert String in K Moves](https://leetcode.com/problems/can-convert-string-in-k-moves) | Medium | `Hash Table`, `String`
1539 | [Kth Missing Positive Number](https://leetcode.com/problems/kth-missing-positive-number) | Easy | `Array`, `Binary Search`
1538 | [Guess the Majority in a Hidden Array](https://leetcode.com/problems/guess-the-majority-in-a-hidden-array) | Medium | `Array`, `Math`, `Interactive`
1537 | [Get the Maximum Score](https://leetcode.com/problems/get-the-maximum-score) | Hard | `Greedy`, `Array`, `Two Pointers`, `Dynamic Programming`
1536 | [Minimum Swaps to Arrange a Binary Grid](https://leetcode.com/problems/minimum-swaps-to-arrange-a-binary-grid) | Medium | `Greedy`, `Array`, `Matrix`
1535 | [Find the Winner of an Array Game](https://leetcode.com/problems/find-the-winner-of-an-array-game) | Medium | `Array`, `Simulation`
1534 | [Count Good Triplets](https://leetcode.com/problems/count-good-triplets) | Easy | `Array`, `Enumeration`
1533 | [Find the Index of the Large Integer](https://leetcode.com/problems/find-the-index-of-the-large-integer) | Medium | `Array`, `Binary Search`, `Interactive`
1532 | [The Most Recent Three Orders](https://leetcode.com/problems/the-most-recent-three-orders) | Medium | `Database`
1531 | [String Compression II](https://leetcode.com/problems/string-compression-ii) | Hard | `String`, `Dynamic Programming`
1530 | [Number of Good Leaf Nodes Pairs](https://leetcode.com/problems/number-of-good-leaf-nodes-pairs) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1529 | [Bulb Switcher IV](https://leetcode.com/problems/bulb-switcher-iv) | Medium | `Greedy`, `String`
1528 | [Shuffle String](https://leetcode.com/problems/shuffle-string) | Easy | `Array`, `String`
1527 | [Patients With a Condition](https://leetcode.com/problems/patients-with-a-condition) | Easy | `Database`
1526 | [Minimum Number of Increments on Subarrays to Form a Target Array](https://leetcode.com/problems/minimum-number-of-increments-on-subarrays-to-form-a-target-array) | Hard | `Stack`, `Greedy`, `Array`, `Dynamic Programming`, `Monotonic Stack`
1525 | [Number of Good Ways to Split a String](https://leetcode.com/problems/number-of-good-ways-to-split-a-string) | Medium | `Bit Manipulation`, `String`, `Dynamic Programming`
1524 | [Number of Sub-arrays With Odd Sum](https://leetcode.com/problems/number-of-sub-arrays-with-odd-sum) | Medium | `Array`, `Math`, `Dynamic Programming`, `Prefix Sum`
1523 | [Count Odd Numbers in an Interval Range](https://leetcode.com/problems/count-odd-numbers-in-an-interval-range) | Easy | `Math`
1522 | [Diameter of N-Ary Tree](https://leetcode.com/problems/diameter-of-n-ary-tree) | Medium | `Tree`, `Depth-First Search`
1521 | [Find a Value of a Mysterious Function Closest to Target](https://leetcode.com/problems/find-a-value-of-a-mysterious-function-closest-to-target) | Hard | `Bit Manipulation`, `Segment Tree`, `Array`, `Binary Search`
1520 | [Maximum Number of Non-Overlapping Substrings](https://leetcode.com/problems/maximum-number-of-non-overlapping-substrings) | Hard | `Greedy`, `String`
1519 | [Number of Nodes in the Sub-Tree With the Same Label](https://leetcode.com/problems/number-of-nodes-in-the-sub-tree-with-the-same-label) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`
1518 | [Water Bottles](https://leetcode.com/problems/water-bottles) | Easy | `Math`, `Simulation`
1517 | [Find Users With Valid E-Mails](https://leetcode.com/problems/find-users-with-valid-e-mails) | Easy | `Database`
1516 | [Move Sub-Tree of N-Ary Tree](https://leetcode.com/problems/move-sub-tree-of-n-ary-tree) | Hard | `Tree`, `Depth-First Search`
1515 | [Best Position for a Service Centre](https://leetcode.com/problems/best-position-for-a-service-centre) | Hard | `Geometry`, `Math`, `Randomized`
1514 | [Path with Maximum Probability](https://leetcode.com/problems/path-with-maximum-probability) | Medium | `Graph`, `Shortest Path`, `Heap (Priority Queue)`
1513 | [Number of Substrings With Only 1s](https://leetcode.com/problems/number-of-substrings-with-only-1s) | Medium | `Math`, `String`
1512 | [Number of Good Pairs](https://leetcode.com/problems/number-of-good-pairs) | Easy | `Array`, `Hash Table`, `Math`, `Counting`
1511 | [Customer Order Frequency](https://leetcode.com/problems/customer-order-frequency) | Easy | `Database`
1510 | [Stone Game IV](https://leetcode.com/problems/stone-game-iv) | Hard | `Math`, `Dynamic Programming`, `Game Theory`
1509 | [Minimum Difference Between Largest and Smallest Value in Three Moves](https://leetcode.com/problems/minimum-difference-between-largest-and-smallest-value-in-three-moves) | Medium | `Greedy`, `Array`, `Sorting`
1508 | [Range Sum of Sorted Subarray Sums](https://leetcode.com/problems/range-sum-of-sorted-subarray-sums) | Medium | `Array`, `Two Pointers`, `Binary Search`, `Sorting`
1507 | [Reformat Date](https://leetcode.com/problems/reformat-date) | Easy | `String`
1506 | [Find Root of N-Ary Tree](https://leetcode.com/problems/find-root-of-n-ary-tree) | Medium | `Bit Manipulation`, `Tree`, `Depth-First Search`, `Hash Table`
1505 | [Minimum Possible Integer After at Most K Adjacent Swaps On Digits](https://leetcode.com/problems/minimum-possible-integer-after-at-most-k-adjacent-swaps-on-digits) | Hard | `Greedy`, `Binary Indexed Tree`, `Segment Tree`, `String`
1504 | [Count Submatrices With All Ones](https://leetcode.com/problems/count-submatrices-with-all-ones) | Medium | `Stack`, `Array`, `Dynamic Programming`, `Matrix`, `Monotonic Stack`
1503 | [Last Moment Before All Ants Fall Out of a Plank](https://leetcode.com/problems/last-moment-before-all-ants-fall-out-of-a-plank) | Medium | `Brainteaser`, `Array`, `Simulation`
1502 | [Can Make Arithmetic Progression From Sequence](https://leetcode.com/problems/can-make-arithmetic-progression-from-sequence) | Easy | `Array`, `Sorting`
1501 | [Countries You Can Safely Invest In](https://leetcode.com/problems/countries-you-can-safely-invest-in) | Medium | `Database`
1500 | [Design a File Sharing System](https://leetcode.com/problems/design-a-file-sharing-system) | Medium | `Design`, `Hash Table`, `Data Stream`, `Heap (Priority Queue)`
1499 | [Max Value of Equation](https://leetcode.com/problems/max-value-of-equation) | Hard | `Queue`, `Array`, `Sliding Window`, `Monotonic Queue`, `Heap (Priority Queue)`
1498 | [Number of Subsequences That Satisfy the Given Sum Condition](https://leetcode.com/problems/number-of-subsequences-that-satisfy-the-given-sum-condition) | Medium | `Array`, `Two Pointers`, `Binary Search`, `Sorting`
1497 | [Check If Array Pairs Are Divisible by k](https://leetcode.com/problems/check-if-array-pairs-are-divisible-by-k) | Medium | `Array`, `Hash Table`, `Counting`
1496 | [Path Crossing](https://leetcode.com/problems/path-crossing) | Easy | `Hash Table`, `String`
1495 | [Friendly Movies Streamed Last Month](https://leetcode.com/problems/friendly-movies-streamed-last-month) | Easy | `Database`
1494 | [Parallel Courses II](https://leetcode.com/problems/parallel-courses-ii) | Hard | `Bit Manipulation`, `Graph`, `Dynamic Programming`, `Bitmask`
1493 | [Longest Subarray of 1's After Deleting One Element](https://leetcode.com/problems/longest-subarray-of-1s-after-deleting-one-element) | Medium | `Math`, `Dynamic Programming`, `Sliding Window`
1492 | [The kth Factor of n](https://leetcode.com/problems/the-kth-factor-of-n) | Medium | `Math`
1491 | [Average Salary Excluding the Minimum and Maximum Salary](https://leetcode.com/problems/average-salary-excluding-the-minimum-and-maximum-salary) | Easy | `Array`, `Sorting`
1490 | [Clone N-ary Tree](https://leetcode.com/problems/clone-n-ary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`
1489 | [Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree](https://leetcode.com/problems/find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree) | Hard | `Union Find`, `Graph`, `Minimum Spanning Tree`, `Sorting`, `Strongly Connected Component`
1488 | [Avoid Flood in The City](https://leetcode.com/problems/avoid-flood-in-the-city) | Medium | `Greedy`, `Array`, `Hash Table`, `Binary Search`, `Heap (Priority Queue)`
1487 | [Making File Names Unique](https://leetcode.com/problems/making-file-names-unique) | Medium | `Array`, `Hash Table`, `String`
1486 | [XOR Operation in an Array](https://leetcode.com/problems/xor-operation-in-an-array) | Easy | `Bit Manipulation`, `Math`
1485 | [Group Sold Products By The Date](https://leetcode.com/problems/group-sold-products-by-the-date) | Easy | `Database`
1484 | [Clone Binary Tree With Random Pointer](https://leetcode.com/problems/clone-binary-tree-with-random-pointer) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`, `Binary Tree`
1483 | [Kth Ancestor of a Tree Node](https://leetcode.com/problems/kth-ancestor-of-a-tree-node) | Hard | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Design`, `Binary Search`, `Dynamic Programming`
1482 | [Minimum Number of Days to Make m Bouquets](https://leetcode.com/problems/minimum-number-of-days-to-make-m-bouquets) | Medium | `Array`, `Binary Search`
1481 | [Least Number of Unique Integers after K Removals](https://leetcode.com/problems/least-number-of-unique-integers-after-k-removals) | Medium | `Greedy`, `Array`, `Hash Table`, `Counting`, `Sorting`
1480 | [Running Sum of 1d Array](https://leetcode.com/problems/running-sum-of-1d-array) | Easy | `Array`, `Prefix Sum`
1479 | [Sales by Day of the Week](https://leetcode.com/problems/sales-by-day-of-the-week) | Hard | `Database`
1478 | [Allocate Mailboxes](https://leetcode.com/problems/allocate-mailboxes) | Hard | `Array`, `Math`, `Dynamic Programming`, `Sorting`
1477 | [Find Two Non-overlapping Sub-arrays Each With Target Sum](https://leetcode.com/problems/find-two-non-overlapping-sub-arrays-each-with-target-sum) | Medium | `Array`, `Hash Table`, `Binary Search`, `Dynamic Programming`, `Sliding Window`
1476 | [Subrectangle Queries](https://leetcode.com/problems/subrectangle-queries) | Medium | `Design`, `Array`, `Matrix`
1475 | [Final Prices With a Special Discount in a Shop](https://leetcode.com/problems/final-prices-with-a-special-discount-in-a-shop) | Easy | `Stack`, `Array`, `Monotonic Stack`
1474 | [Delete N Nodes After M Nodes of a Linked List](https://leetcode.com/problems/delete-n-nodes-after-m-nodes-of-a-linked-list) | Easy | `Linked List`
1473 | [Paint House III](https://leetcode.com/problems/paint-house-iii) | Hard | `Array`, `Dynamic Programming`
1472 | [Design Browser History](https://leetcode.com/problems/design-browser-history) | Medium | `Stack`, `Design`, `Array`, `Linked List`, `Data Stream`, `Doubly-Linked List`
1471 | [The k Strongest Values in an Array](https://leetcode.com/problems/the-k-strongest-values-in-an-array) | Medium | `Array`, `Two Pointers`, `Sorting`
1470 | [Shuffle the Array](https://leetcode.com/problems/shuffle-the-array) | Easy | `Array`
1469 | [Find All The Lonely Nodes](https://leetcode.com/problems/find-all-the-lonely-nodes) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
1468 | [Calculate Salaries](https://leetcode.com/problems/calculate-salaries) | Medium | `Database`
1467 | [Probability of a Two Boxes Having The Same Number of Distinct Balls](https://leetcode.com/problems/probability-of-a-two-boxes-having-the-same-number-of-distinct-balls) | Hard | `Math`, `Dynamic Programming`, `Backtracking`, `Combinatorics`, `Probability and Statistics`
1466 | [Reorder Routes to Make All Paths Lead to the City Zero](https://leetcode.com/problems/reorder-routes-to-make-all-paths-lead-to-the-city-zero) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`
1465 | [Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts](https://leetcode.com/problems/maximum-area-of-a-piece-of-cake-after-horizontal-and-vertical-cuts) | Medium | `Greedy`, `Array`, `Sorting`
1464 | [Maximum Product of Two Elements in an Array](https://leetcode.com/problems/maximum-product-of-two-elements-in-an-array) | Easy | `Array`, `Sorting`, `Heap (Priority Queue)`
1463 | [Cherry Pickup II](https://leetcode.com/problems/cherry-pickup-ii) | Hard | `Array`, `Dynamic Programming`, `Matrix`
1462 | [Course Schedule IV](https://leetcode.com/problems/course-schedule-iv) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Topological Sort`
1461 | [Check If a String Contains All Binary Codes of Size K](https://leetcode.com/problems/check-if-a-string-contains-all-binary-codes-of-size-k) | Medium | `Bit Manipulation`, `Hash Table`, `String`, `Hash Function`, `Rolling Hash`
1460 | [Make Two Arrays Equal by Reversing Sub-arrays](https://leetcode.com/problems/make-two-arrays-equal-by-reversing-sub-arrays) | Easy | `Array`, `Hash Table`, `Sorting`
1459 | [Rectangles Area](https://leetcode.com/problems/rectangles-area) | Medium | `Database`
1458 | [Max Dot Product of Two Subsequences](https://leetcode.com/problems/max-dot-product-of-two-subsequences) | Hard | `Array`, `Dynamic Programming`
1457 | [Pseudo-Palindromic Paths in a Binary Tree](https://leetcode.com/problems/pseudo-palindromic-paths-in-a-binary-tree) | Medium | `Bit Manipulation`, `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
1456 | [Maximum Number of Vowels in a Substring of Given Length](https://leetcode.com/problems/maximum-number-of-vowels-in-a-substring-of-given-length) | Medium | `String`, `Sliding Window`
1455 | [Check If a Word Occurs As a Prefix of Any Word in a Sentence](https://leetcode.com/problems/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence) | Easy | `String`, `String Matching`
1454 | [Active Users](https://leetcode.com/problems/active-users) | Medium | `Database`
1453 | [Maximum Number of Darts Inside of a Circular Dartboard](https://leetcode.com/problems/maximum-number-of-darts-inside-of-a-circular-dartboard) | Hard | `Geometry`, `Array`, `Math`
1452 | [People Whose List of Favorite Companies Is Not a Subset of Another List](https://leetcode.com/problems/people-whose-list-of-favorite-companies-is-not-a-subset-of-another-list) | Medium | `Array`, `Hash Table`, `String`
1451 | [Rearrange Words in a Sentence](https://leetcode.com/problems/rearrange-words-in-a-sentence) | Medium | `String`, `Sorting`
1450 | [Number of Students Doing Homework at a Given Time](https://leetcode.com/problems/number-of-students-doing-homework-at-a-given-time) | Easy | `Array`
1449 | [Form Largest Integer With Digits That Add up to Target](https://leetcode.com/problems/form-largest-integer-with-digits-that-add-up-to-target) | Hard | `Array`, `Dynamic Programming`
1448 | [Count Good Nodes in Binary Tree](https://leetcode.com/problems/count-good-nodes-in-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
1447 | [Simplified Fractions](https://leetcode.com/problems/simplified-fractions) | Medium | `Math`
1446 | [Consecutive Characters](https://leetcode.com/problems/consecutive-characters) | Easy | `String`
1445 | [Apples & Oranges](https://leetcode.com/problems/apples-oranges) | Medium | `Database`
1444 | [Number of Ways of Cutting a Pizza](https://leetcode.com/problems/number-of-ways-of-cutting-a-pizza) | Hard | `Memoization`, `Array`, `Dynamic Programming`, `Matrix`
1443 | [Minimum Time to Collect All Apples in a Tree](https://leetcode.com/problems/minimum-time-to-collect-all-apples-in-a-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`
1442 | [Count Triplets That Can Form Two Arrays of Equal XOR](https://leetcode.com/problems/count-triplets-that-can-form-two-arrays-of-equal-xor) | Medium | `Bit Manipulation`, `Array`, `Hash Table`, `Math`, `Prefix Sum`
1441 | [Build an Array With Stack Operations](https://leetcode.com/problems/build-an-array-with-stack-operations) | Easy | `Stack`, `Array`, `Simulation`
1440 | [Evaluate Boolean Expression](https://leetcode.com/problems/evaluate-boolean-expression) | Medium | `Database`
1439 | [Find the Kth Smallest Sum of a Matrix With Sorted Rows](https://leetcode.com/problems/find-the-kth-smallest-sum-of-a-matrix-with-sorted-rows) | Hard | `Array`, `Binary Search`, `Matrix`, `Heap (Priority Queue)`
1438 | [Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit](https://leetcode.com/problems/longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit) | Medium | `Queue`, `Array`, `Ordered Set`, `Sliding Window`, `Monotonic Queue`, `Heap (Priority Queue)`
1437 | [Check If All 1's Are at Least Length K Places Away](https://leetcode.com/problems/check-if-all-1s-are-at-least-length-k-places-away) | Easy | `Array`
1436 | [Destination City](https://leetcode.com/problems/destination-city) | Easy | `Hash Table`, `String`
1435 | [Create a Session Bar Chart](https://leetcode.com/problems/create-a-session-bar-chart) | Easy | `Database`
1434 | [Number of Ways to Wear Different Hats to Each Other](https://leetcode.com/problems/number-of-ways-to-wear-different-hats-to-each-other) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Bitmask`
1433 | [Check If a String Can Break Another String](https://leetcode.com/problems/check-if-a-string-can-break-another-string) | Medium | `Greedy`, `String`, `Sorting`
1432 | [Max Difference You Can Get From Changing an Integer](https://leetcode.com/problems/max-difference-you-can-get-from-changing-an-integer) | Medium | `Greedy`, `Math`
1431 | [Kids With the Greatest Number of Candies](https://leetcode.com/problems/kids-with-the-greatest-number-of-candies) | Easy | `Array`
1430 | [Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree](https://leetcode.com/problems/check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
1429 | [First Unique Number](https://leetcode.com/problems/first-unique-number) | Medium | `Design`, `Queue`, `Array`, `Hash Table`, `Data Stream`
1428 | [Leftmost Column with at Least a One](https://leetcode.com/problems/leftmost-column-with-at-least-a-one) | Medium | `Array`, `Binary Search`, `Interactive`, `Matrix`
1427 | [Perform String Shifts](https://leetcode.com/problems/perform-string-shifts) | Easy | `Array`, `Math`, `String`
1426 | [Counting Elements](https://leetcode.com/problems/counting-elements) | Easy | `Array`, `Hash Table`
1425 | [Constrained Subsequence Sum](https://leetcode.com/problems/constrained-subsequence-sum) | Hard | `Queue`, `Array`, `Dynamic Programming`, `Sliding Window`, `Monotonic Queue`, `Heap (Priority Queue)`
1424 | [Diagonal Traverse II](https://leetcode.com/problems/diagonal-traverse-ii) | Medium | `Array`, `Sorting`, `Heap (Priority Queue)`
1423 | [Maximum Points You Can Obtain from Cards](https://leetcode.com/problems/maximum-points-you-can-obtain-from-cards) | Medium | `Array`, `Prefix Sum`, `Sliding Window`
1422 | [Maximum Score After Splitting a String](https://leetcode.com/problems/maximum-score-after-splitting-a-string) | Easy | `String`
1421 | [NPV Queries](https://leetcode.com/problems/npv-queries) | Easy | `Database`
1420 | [Build Array Where You Can Find The Maximum Exactly K Comparisons](https://leetcode.com/problems/build-array-where-you-can-find-the-maximum-exactly-k-comparisons) | Hard | `Dynamic Programming`
1417 | [Reformat The String](https://leetcode.com/problems/reformat-the-string) | Easy | `String`
1416 | [Restore The Array](https://leetcode.com/problems/restore-the-array) | Hard | `String`, `Dynamic Programming`
1415 | [The k-th Lexicographical String of All Happy Strings of Length n](https://leetcode.com/problems/the-k-th-lexicographical-string-of-all-happy-strings-of-length-n) | Medium | `String`, `Backtracking`
1414 | [Find the Minimum Number of Fibonacci Numbers Whose Sum Is K](https://leetcode.com/problems/find-the-minimum-number-of-fibonacci-numbers-whose-sum-is-k) | Medium | `Greedy`
1413 | [Minimum Value to Get Positive Step by Step Sum](https://leetcode.com/problems/minimum-value-to-get-positive-step-by-step-sum) | Easy | `Array`, `Prefix Sum`
1412 | [Find the Quiet Students in All Exams](https://leetcode.com/problems/find-the-quiet-students-in-all-exams) | Hard | `Database`
1411 | [Number of Ways to Paint N × 3 Grid](https://leetcode.com/problems/number-of-ways-to-paint-n-3-grid) | Hard | `Dynamic Programming`
1410 | [HTML Entity Parser](https://leetcode.com/problems/html-entity-parser) | Medium | `Hash Table`, `String`
1409 | [Queries on a Permutation With Key](https://leetcode.com/problems/queries-on-a-permutation-with-key) | Medium | `Binary Indexed Tree`, `Array`, `Simulation`
1408 | [String Matching in an Array](https://leetcode.com/problems/string-matching-in-an-array) | Easy | `String`, `String Matching`
1407 | [Top Travellers](https://leetcode.com/problems/top-travellers) | Easy | `Database`
1406 | [Stone Game III](https://leetcode.com/problems/stone-game-iii) | Hard | `Array`, `Math`, `Dynamic Programming`, `Game Theory`
1405 | [Longest Happy String](https://leetcode.com/problems/longest-happy-string) | Medium | `Greedy`, `String`, `Heap (Priority Queue)`
1404 | [Number of Steps to Reduce a Number in Binary Representation to One](https://leetcode.com/problems/number-of-steps-to-reduce-a-number-in-binary-representation-to-one) | Medium | `Bit Manipulation`, `String`
1403 | [Minimum Subsequence in Non-Increasing Order](https://leetcode.com/problems/minimum-subsequence-in-non-increasing-order) | Easy | `Greedy`, `Array`, `Sorting`
1402 | [Reducing Dishes](https://leetcode.com/problems/reducing-dishes) | Hard | `Greedy`, `Array`, `Dynamic Programming`, `Sorting`
1401 | [Circle and Rectangle Overlapping](https://leetcode.com/problems/circle-and-rectangle-overlapping) | Medium | `Geometry`, `Math`
1400 | [Construct K Palindrome Strings](https://leetcode.com/problems/construct-k-palindrome-strings) | Medium | `Greedy`, `Hash Table`, `String`, `Counting`
1399 | [Count Largest Group](https://leetcode.com/problems/count-largest-group) | Easy | `Hash Table`, `Math`
1398 | [Customers Who Bought Products A and B but Not C](https://leetcode.com/problems/customers-who-bought-products-a-and-b-but-not-c) | Medium | `Database`
1397 | [Find All Good Strings](https://leetcode.com/problems/find-all-good-strings) | Hard | `String`, `Dynamic Programming`, `String Matching`
1396 | [Design Underground System](https://leetcode.com/problems/design-underground-system) | Medium | `Design`, `Hash Table`, `String`
1395 | [Count Number of Teams](https://leetcode.com/problems/count-number-of-teams) | Medium | `Binary Indexed Tree`, `Array`, `Dynamic Programming`
1394 | [Find Lucky Integer in an Array](https://leetcode.com/problems/find-lucky-integer-in-an-array) | Easy | `Array`, `Hash Table`, `Counting`
1393 | [Capital Gain/Loss](https://leetcode.com/problems/capital-gainloss) | Medium | `Database`
1392 | [Longest Happy Prefix](https://leetcode.com/problems/longest-happy-prefix) | Hard | `String`, `String Matching`, `Hash Function`, `Rolling Hash`
1391 | [Check if There is a Valid Path in a Grid](https://leetcode.com/problems/check-if-there-is-a-valid-path-in-a-grid) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
1390 | [Four Divisors](https://leetcode.com/problems/four-divisors) | Medium | `Array`, `Math`
1389 | [Create Target Array in the Given Order](https://leetcode.com/problems/create-target-array-in-the-given-order) | Easy | `Array`, `Simulation`
1388 | [Pizza With 3n Slices](https://leetcode.com/problems/pizza-with-3n-slices) | Hard | `Greedy`, `Array`, `Dynamic Programming`, `Heap (Priority Queue)`
1387 | [Sort Integers by The Power Value](https://leetcode.com/problems/sort-integers-by-the-power-value) | Medium | `Memoization`, `Dynamic Programming`, `Sorting`
1386 | [Cinema Seat Allocation](https://leetcode.com/problems/cinema-seat-allocation) | Medium | `Greedy`, `Bit Manipulation`, `Array`, `Hash Table`
1385 | [Find the Distance Value Between Two Arrays](https://leetcode.com/problems/find-the-distance-value-between-two-arrays) | Easy | `Array`, `Two Pointers`, `Binary Search`, `Sorting`
1384 | [Total Sales Amount by Year](https://leetcode.com/problems/total-sales-amount-by-year) | Hard | `Database`
1382 | [Balance a Binary Search Tree](https://leetcode.com/problems/balance-a-binary-search-tree) | Medium | `Greedy`, `Tree`, `Depth-First Search`, `Binary Search Tree`, `Divide and Conquer`, `Binary Tree`
1381 | [Design a Stack With Increment Operation](https://leetcode.com/problems/design-a-stack-with-increment-operation) | Medium | `Stack`, `Design`, `Array`
1380 | [Lucky Numbers in a Matrix](https://leetcode.com/problems/lucky-numbers-in-a-matrix) | Easy | `Array`, `Matrix`
1379 | [Find a Corresponding Node of a Binary Tree in a Clone of That Tree](https://leetcode.com/problems/find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
1378 | [Replace Employee ID With The Unique Identifier](https://leetcode.com/problems/replace-employee-id-with-the-unique-identifier) | Easy | `Database`
1377 | [Frog Position After T Seconds](https://leetcode.com/problems/frog-position-after-t-seconds) | Hard | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Graph`
1376 | [Time Needed to Inform All Employees](https://leetcode.com/problems/time-needed-to-inform-all-employees) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`
1375 | [Bulb Switcher III](https://leetcode.com/problems/bulb-switcher-iii) | Medium | `Array`
1374 | [Generate a String With Characters That Have Odd Counts](https://leetcode.com/problems/generate-a-string-with-characters-that-have-odd-counts) | Easy | `String`
1373 | [Maximum Sum BST in Binary Tree](https://leetcode.com/problems/maximum-sum-bst-in-binary-tree) | Hard | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Dynamic Programming`, `Binary Tree`
1372 | [Longest ZigZag Path in a Binary Tree](https://leetcode.com/problems/longest-zigzag-path-in-a-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Dynamic Programming`, `Binary Tree`
1371 | [Find the Longest Substring Containing Vowels in Even Counts](https://leetcode.com/problems/find-the-longest-substring-containing-vowels-in-even-counts) | Medium | `Bit Manipulation`, `Hash Table`, `String`, `Prefix Sum`
1370 | [Increasing Decreasing String](https://leetcode.com/problems/increasing-decreasing-string) | Easy | `Hash Table`, `String`, `Counting`
1369 | [Get the Second Most Recent Activity](https://leetcode.com/problems/get-the-second-most-recent-activity) | Hard | `Database`
1368 | [Minimum Cost to Make at Least One Valid Path in a Grid](https://leetcode.com/problems/minimum-cost-to-make-at-least-one-valid-path-in-a-grid) | Hard | `Breadth-First Search`, `Graph`, `Array`, `Matrix`, `Shortest Path`, `Heap (Priority Queue)`
1367 | [Linked List in Binary Tree](https://leetcode.com/problems/linked-list-in-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Linked List`, `Binary Tree`
1366 | [Rank Teams by Votes](https://leetcode.com/problems/rank-teams-by-votes) | Medium | `Array`, `Hash Table`, `String`, `Counting`, `Sorting`
1365 | [How Many Numbers Are Smaller Than the Current Number](https://leetcode.com/problems/how-many-numbers-are-smaller-than-the-current-number) | Easy | `Array`, `Hash Table`, `Counting`, `Sorting`
1364 | [Number of Trusted Contacts of a Customer](https://leetcode.com/problems/number-of-trusted-contacts-of-a-customer) | Medium | `Database`
1363 | [Largest Multiple of Three](https://leetcode.com/problems/largest-multiple-of-three) | Hard | `Greedy`, `Array`, `Dynamic Programming`
1362 | [Closest Divisors](https://leetcode.com/problems/closest-divisors) | Medium | `Math`
1361 | [Validate Binary Tree Nodes](https://leetcode.com/problems/validate-binary-tree-nodes) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`, `Binary Tree`
1359 | [Count All Valid Pickup and Delivery Options](https://leetcode.com/problems/count-all-valid-pickup-and-delivery-options) | Hard | `Math`, `Dynamic Programming`, `Combinatorics`
1358 | [Number of Substrings Containing All Three Characters](https://leetcode.com/problems/number-of-substrings-containing-all-three-characters) | Medium | `Hash Table`, `String`, `Sliding Window`
1357 | [Apply Discount Every n Orders](https://leetcode.com/problems/apply-discount-every-n-orders) | Medium | `Design`, `Array`, `Hash Table`
1356 | [Sort Integers by The Number of 1 Bits](https://leetcode.com/problems/sort-integers-by-the-number-of-1-bits) | Easy | `Bit Manipulation`, `Array`, `Counting`, `Sorting`
1355 | [Activity Participants](https://leetcode.com/problems/activity-participants) | Medium | `Database`
1354 | [Construct Target Array With Multiple Sums](https://leetcode.com/problems/construct-target-array-with-multiple-sums) | Hard | `Array`, `Heap (Priority Queue)`
1353 | [Maximum Number of Events That Can Be Attended](https://leetcode.com/problems/maximum-number-of-events-that-can-be-attended) | Medium | `Greedy`, `Array`, `Heap (Priority Queue)`
1352 | [Product of the Last K Numbers](https://leetcode.com/problems/product-of-the-last-k-numbers) | Medium | `Design`, `Queue`, `Array`, `Math`, `Data Stream`
1351 | [Count Negative Numbers in a Sorted Matrix](https://leetcode.com/problems/count-negative-numbers-in-a-sorted-matrix) | Easy | `Array`, `Binary Search`, `Matrix`
1350 | [Students With Invalid Departments](https://leetcode.com/problems/students-with-invalid-departments) | Easy | `Database`
1349 | [Maximum Students Taking Exam](https://leetcode.com/problems/maximum-students-taking-exam) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Bitmask`, `Matrix`
1348 | [Tweet Counts Per Frequency](https://leetcode.com/problems/tweet-counts-per-frequency) | Medium | `Design`, `Hash Table`, `Binary Search`, `Ordered Set`, `Sorting`
1347 | [Minimum Number of Steps to Make Two Strings Anagram](https://leetcode.com/problems/minimum-number-of-steps-to-make-two-strings-anagram) | Medium | `Hash Table`, `String`
1346 | [Check If N and Its Double Exist](https://leetcode.com/problems/check-if-n-and-its-double-exist) | Easy | `Array`, `Hash Table`, `Two Pointers`, `Binary Search`, `Sorting`
1345 | [Jump Game IV](https://leetcode.com/problems/jump-game-iv) | Hard | `Breadth-First Search`, `Array`, `Hash Table`
1344 | [Angle Between Hands of a Clock](https://leetcode.com/problems/angle-between-hands-of-a-clock) | Medium | `Math`
1343 | [Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold](https://leetcode.com/problems/number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold) | Medium | `Array`, `Sliding Window`
1342 | [Number of Steps to Reduce a Number to Zero](https://leetcode.com/problems/number-of-steps-to-reduce-a-number-to-zero) | Easy | `Bit Manipulation`, `Math`
1341 | [Movie Rating](https://leetcode.com/problems/movie-rating) | Medium | `Database`
1340 | [Jump Game V](https://leetcode.com/problems/jump-game-v) | Hard | `Array`, `Dynamic Programming`, `Sorting`
1339 | [Maximum Product of Splitted Binary Tree](https://leetcode.com/problems/maximum-product-of-splitted-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1338 | [Reduce Array Size to The Half](https://leetcode.com/problems/reduce-array-size-to-the-half) | Medium | `Greedy`, `Array`, `Hash Table`, `Sorting`, `Heap (Priority Queue)`
1336 | [Number of Transactions per Visit](https://leetcode.com/problems/number-of-transactions-per-visit) | Hard | `Database`
1335 | [Minimum Difficulty of a Job Schedule](https://leetcode.com/problems/minimum-difficulty-of-a-job-schedule) | Hard | `Array`, `Dynamic Programming`
1334 | [Find the City With the Smallest Number of Neighbors at a Threshold Distance](https://leetcode.com/problems/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance) | Medium | `Graph`, `Dynamic Programming`, `Shortest Path`
1333 | [Filter Restaurants by Vegan-Friendly, Price and Distance](https://leetcode.com/problems/filter-restaurants-by-vegan-friendly-price-and-distance) | Medium | `Array`, `Sorting`
1332 | [Remove Palindromic Subsequences](https://leetcode.com/problems/remove-palindromic-subsequences) | Easy | `Two Pointers`, `String`
1331 | [Rank Transform of an Array](https://leetcode.com/problems/rank-transform-of-an-array) | Easy | `Array`, `Hash Table`, `Sorting`
1330 | [Reverse Subarray To Maximize Array Value](https://leetcode.com/problems/reverse-subarray-to-maximize-array-value) | Hard | `Greedy`, `Array`, `Math`
1329 | [Sort the Matrix Diagonally](https://leetcode.com/problems/sort-the-matrix-diagonally) | Medium | `Array`, `Matrix`, `Sorting`
1328 | [Break a Palindrome](https://leetcode.com/problems/break-a-palindrome) | Medium | `Greedy`, `String`
1327 | [List the Products Ordered in a Period](https://leetcode.com/problems/list-the-products-ordered-in-a-period) | Easy | `Database`
1326 | [Minimum Number of Taps to Open to Water a Garden](https://leetcode.com/problems/minimum-number-of-taps-to-open-to-water-a-garden) | Hard | `Greedy`, `Array`, `Dynamic Programming`
1325 | [Delete Leaves With a Given Value](https://leetcode.com/problems/delete-leaves-with-a-given-value) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`, `Binary Tree`
1324 | [Print Words Vertically](https://leetcode.com/problems/print-words-vertically) | Medium | `Array`, `String`, `Simulation`
1323 | [Maximum 69 Number](https://leetcode.com/problems/maximum-69-number) | Easy | `Greedy`, `Math`
1322 | [Ads Performance](https://leetcode.com/problems/ads-performance) | Easy | `Database`
1321 | [Restaurant Growth](https://leetcode.com/problems/restaurant-growth) | Medium | `Database`
1320 | [Minimum Distance to Type a Word Using Two Fingers](https://leetcode.com/problems/minimum-distance-to-type-a-word-using-two-fingers) | Hard | `String`, `Dynamic Programming`
1319 | [Number of Operations to Make Network Connected](https://leetcode.com/problems/number-of-operations-to-make-network-connected) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
1318 | [Minimum Flips to Make a OR b Equal to c](https://leetcode.com/problems/minimum-flips-to-make-a-or-b-equal-to-c) | Medium | `Bit Manipulation`
1317 | [Convert Integer to the Sum of Two No-Zero Integers](https://leetcode.com/problems/convert-integer-to-the-sum-of-two-no-zero-integers) | Easy | `Math`
1316 | [Distinct Echo Substrings](https://leetcode.com/problems/distinct-echo-substrings) | Hard | `Trie`, `String`, `Dynamic Programming`, `Sliding Window`, `Hash Function`, `Rolling Hash`
1315 | [Sum of Nodes with Even-Valued Grandparent](https://leetcode.com/problems/sum-of-nodes-with-even-valued-grandparent) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
1314 | [Matrix Block Sum](https://leetcode.com/problems/matrix-block-sum) | Medium | `Array`, `Matrix`, `Prefix Sum`
1313 | [Decompress Run-Length Encoded List](https://leetcode.com/problems/decompress-run-length-encoded-list) | Easy | `Array`
1312 | [Minimum Insertion Steps to Make a String Palindrome](https://leetcode.com/problems/minimum-insertion-steps-to-make-a-string-palindrome) | Hard | `String`, `Dynamic Programming`
1311 | [Get Watched Videos by Your Friends](https://leetcode.com/problems/get-watched-videos-by-your-friends) | Medium | `Breadth-First Search`, `Array`, `Hash Table`, `Sorting`
1310 | [XOR Queries of a Subarray](https://leetcode.com/problems/xor-queries-of-a-subarray) | Medium | `Bit Manipulation`, `Array`, `Prefix Sum`
1309 | [Decrypt String from Alphabet to Integer Mapping](https://leetcode.com/problems/decrypt-string-from-alphabet-to-integer-mapping) | Easy | `String`
1308 | [Running Total for Different Genders](https://leetcode.com/problems/running-total-for-different-genders) | Medium | `Database`
1307 | [Verbal Arithmetic Puzzle](https://leetcode.com/problems/verbal-arithmetic-puzzle) | Hard | `Array`, `Math`, `String`, `Backtracking`
1306 | [Jump Game III](https://leetcode.com/problems/jump-game-iii) | Medium | `Depth-First Search`, `Breadth-First Search`, `Array`
1305 | [All Elements in Two Binary Search Trees](https://leetcode.com/problems/all-elements-in-two-binary-search-trees) | Medium | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`, `Sorting`
1304 | [Find N Unique Integers Sum up to Zero](https://leetcode.com/problems/find-n-unique-integers-sum-up-to-zero) | Easy | `Array`, `Math`
1303 | [Find the Team Size](https://leetcode.com/problems/find-the-team-size) | Easy | `Database`
1302 | [Deepest Leaves Sum](https://leetcode.com/problems/deepest-leaves-sum) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
1301 | [Number of Paths with Max Score](https://leetcode.com/problems/number-of-paths-with-max-score) | Hard | `Array`, `Dynamic Programming`, `Matrix`
1300 | [Sum of Mutated Array Closest to Target](https://leetcode.com/problems/sum-of-mutated-array-closest-to-target) | Medium | `Array`, `Binary Search`, `Sorting`
1299 | [Replace Elements with Greatest Element on Right Side](https://leetcode.com/problems/replace-elements-with-greatest-element-on-right-side) | Easy | `Array`
1298 | [Maximum Candies You Can Get from Boxes](https://leetcode.com/problems/maximum-candies-you-can-get-from-boxes) | Hard | `Breadth-First Search`, `Array`
1297 | [Maximum Number of Occurrences of a Substring](https://leetcode.com/problems/maximum-number-of-occurrences-of-a-substring) | Medium | `Hash Table`, `String`, `Sliding Window`
1296 | [Divide Array in Sets of K Consecutive Numbers](https://leetcode.com/problems/divide-array-in-sets-of-k-consecutive-numbers) | Medium | `Greedy`, `Array`, `Hash Table`, `Sorting`
1294 | [Weather Type in Each Country](https://leetcode.com/problems/weather-type-in-each-country) | Easy | `Database`
1293 | [Shortest Path in a Grid with Obstacles Elimination](https://leetcode.com/problems/shortest-path-in-a-grid-with-obstacles-elimination) | Hard | `Breadth-First Search`, `Array`, `Matrix`
1292 | [Maximum Side Length of a Square with Sum Less than or Equal to Threshold](https://leetcode.com/problems/maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold) | Medium | `Array`, `Binary Search`, `Matrix`, `Prefix Sum`
1291 | [Sequential Digits](https://leetcode.com/problems/sequential-digits) | Medium | `Enumeration`
1290 | [Convert Binary Number in a Linked List to Integer](https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer) | Easy | `Linked List`, `Math`
1289 | [Minimum Falling Path Sum II](https://leetcode.com/problems/minimum-falling-path-sum-ii) | Hard | `Array`, `Dynamic Programming`, `Matrix`
1288 | [Remove Covered Intervals](https://leetcode.com/problems/remove-covered-intervals) | Medium | `Array`, `Sorting`
1287 | [Element Appearing More Than 25% In Sorted Array](https://leetcode.com/problems/element-appearing-more-than-25-in-sorted-array) | Easy | `Array`
1286 | [Iterator for Combination](https://leetcode.com/problems/iterator-for-combination) | Medium | `Design`, `String`, `Backtracking`, `Iterator`
1285 | [Find the Start and End Number of Continuous Ranges](https://leetcode.com/problems/find-the-start-and-end-number-of-continuous-ranges) | Medium | `Database`
1284 | [Minimum Number of Flips to Convert Binary Matrix to Zero Matrix](https://leetcode.com/problems/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix) | Hard | `Bit Manipulation`, `Breadth-First Search`, `Array`, `Matrix`
1283 | [Find the Smallest Divisor Given a Threshold](https://leetcode.com/problems/find-the-smallest-divisor-given-a-threshold) | Medium | `Array`, `Binary Search`
1282 | [Group the People Given the Group Size They Belong To](https://leetcode.com/problems/group-the-people-given-the-group-size-they-belong-to) | Medium | `Array`, `Hash Table`
1281 | [Subtract the Product and Sum of Digits of an Integer](https://leetcode.com/problems/subtract-the-product-and-sum-of-digits-of-an-integer) | Easy | `Math`
1280 | [Students and Examinations](https://leetcode.com/problems/students-and-examinations) | Easy | `Database`
1279 | [Traffic Light Controlled Intersection](https://leetcode.com/problems/traffic-light-controlled-intersection) | Easy | `Concurrency`
1278 | [Palindrome Partitioning III](https://leetcode.com/problems/palindrome-partitioning-iii) | Hard | `String`, `Dynamic Programming`
1277 | [Count Square Submatrices with All Ones](https://leetcode.com/problems/count-square-submatrices-with-all-ones) | Medium | `Array`, `Dynamic Programming`, `Matrix`
1276 | [Number of Burgers with No Waste of Ingredients](https://leetcode.com/problems/number-of-burgers-with-no-waste-of-ingredients) | Medium | `Math`
1275 | [Find Winner on a Tic Tac Toe Game](https://leetcode.com/problems/find-winner-on-a-tic-tac-toe-game) | Easy | `Array`, `Hash Table`, `Matrix`, `Simulation`
1274 | [Number of Ships in a Rectangle](https://leetcode.com/problems/number-of-ships-in-a-rectangle) | Hard | `Array`, `Divide and Conquer`, `Interactive`
1273 | [Delete Tree Nodes](https://leetcode.com/problems/delete-tree-nodes) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`
1272 | [Remove Interval](https://leetcode.com/problems/remove-interval) | Medium | `Array`
1271 | [Hexspeak](https://leetcode.com/problems/hexspeak) | Easy | `Math`, `String`
1270 | [All People Report to the Given Manager](https://leetcode.com/problems/all-people-report-to-the-given-manager) | Medium | `Database`
1269 | [Number of Ways to Stay in the Same Place After Some Steps](https://leetcode.com/problems/number-of-ways-to-stay-in-the-same-place-after-some-steps) | Hard | `Dynamic Programming`
1268 | [Search Suggestions System](https://leetcode.com/problems/search-suggestions-system) | Medium | `Trie`, `Array`, `String`
1267 | [Count Servers that Communicate](https://leetcode.com/problems/count-servers-that-communicate) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Counting`, `Matrix`
1266 | [Minimum Time Visiting All Points](https://leetcode.com/problems/minimum-time-visiting-all-points) | Easy | `Geometry`, `Array`, `Math`
1265 | [Print Immutable Linked List in Reverse](https://leetcode.com/problems/print-immutable-linked-list-in-reverse) | Medium | `Stack`, `Recursion`, `Linked List`, `Two Pointers`
1264 | [Page Recommendations](https://leetcode.com/problems/page-recommendations) | Medium | `Database`
1263 | [Minimum Moves to Move a Box to Their Target Location](https://leetcode.com/problems/minimum-moves-to-move-a-box-to-their-target-location) | Hard | `Breadth-First Search`, `Array`, `Matrix`, `Heap (Priority Queue)`
1262 | [Greatest Sum Divisible by Three](https://leetcode.com/problems/greatest-sum-divisible-by-three) | Medium | `Greedy`, `Array`, `Dynamic Programming`
1261 | [Find Elements in a Contaminated Binary Tree](https://leetcode.com/problems/find-elements-in-a-contaminated-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Design`, `Binary Tree`
1260 | [Shift 2D Grid](https://leetcode.com/problems/shift-2d-grid) | Easy | `Array`, `Matrix`, `Simulation`
1259 | [Handshakes That Don't Cross](https://leetcode.com/problems/handshakes-that-dont-cross) | Hard | `Math`, `Dynamic Programming`
1258 | [Synonymous Sentences](https://leetcode.com/problems/synonymous-sentences) | Medium | `Union Find`, `Array`, `Hash Table`, `String`, `Backtracking`
1257 | [Smallest Common Region](https://leetcode.com/problems/smallest-common-region) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Array`, `Hash Table`, `String`
1256 | [Encode Number](https://leetcode.com/problems/encode-number) | Medium | `Bit Manipulation`, `Math`, `String`
1255 | [Maximum Score Words Formed by Letters](https://leetcode.com/problems/maximum-score-words-formed-by-letters) | Hard | `Bit Manipulation`, `Array`, `String`, `Dynamic Programming`, `Backtracking`, `Bitmask`
1254 | [Number of Closed Islands](https://leetcode.com/problems/number-of-closed-islands) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
1253 | [Reconstruct a 2-Row Binary Matrix](https://leetcode.com/problems/reconstruct-a-2-row-binary-matrix) | Medium | `Greedy`, `Array`, `Matrix`
1252 | [Cells with Odd Values in a Matrix](https://leetcode.com/problems/cells-with-odd-values-in-a-matrix) | Easy | `Array`, `Math`, `Simulation`
1251 | [Average Selling Price](https://leetcode.com/problems/average-selling-price) | Easy | `Database`
1250 | [Check If It Is a Good Array](https://leetcode.com/problems/check-if-it-is-a-good-array) | Hard | `Array`, `Math`, `Number Theory`
1249 | [Minimum Remove to Make Valid Parentheses](https://leetcode.com/problems/minimum-remove-to-make-valid-parentheses) | Medium | `Stack`, `String`
1248 | [Count Number of Nice Subarrays](https://leetcode.com/problems/count-number-of-nice-subarrays) | Medium | `Array`, `Hash Table`, `Math`, `Sliding Window`
1247 | [Minimum Swaps to Make Strings Equal](https://leetcode.com/problems/minimum-swaps-to-make-strings-equal) | Medium | `Greedy`, `Math`, `String`
1246 | [Palindrome Removal](https://leetcode.com/problems/palindrome-removal) | Hard | `Array`, `Dynamic Programming`
1245 | [Tree Diameter](https://leetcode.com/problems/tree-diameter) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`
1244 | [Design A Leaderboard](https://leetcode.com/problems/design-a-leaderboard) | Medium | `Design`, `Hash Table`, `Sorting`
1243 | [Array Transformation](https://leetcode.com/problems/array-transformation) | Easy | `Array`, `Simulation`
1242 | [Web Crawler Multithreaded](https://leetcode.com/problems/web-crawler-multithreaded) | Medium | `Depth-First Search`, `Breadth-First Search`, `Concurrency`
1241 | [Number of Comments per Post](https://leetcode.com/problems/number-of-comments-per-post) | Easy | `Database`
1240 | [Tiling a Rectangle with the Fewest Squares](https://leetcode.com/problems/tiling-a-rectangle-with-the-fewest-squares) | Hard | `Dynamic Programming`, `Backtracking`
1239 | [Maximum Length of a Concatenated String with Unique Characters](https://leetcode.com/problems/maximum-length-of-a-concatenated-string-with-unique-characters) | Medium | `Bit Manipulation`, `Array`, `String`, `Backtracking`
1238 | [Circular Permutation in Binary Representation](https://leetcode.com/problems/circular-permutation-in-binary-representation) | Medium | `Bit Manipulation`, `Math`, `Backtracking`
1237 | [Find Positive Integer Solution for a Given Equation](https://leetcode.com/problems/find-positive-integer-solution-for-a-given-equation) | Medium | `Math`, `Two Pointers`, `Binary Search`, `Interactive`
1236 | [Web Crawler](https://leetcode.com/problems/web-crawler) | Medium | `Depth-First Search`, `Breadth-First Search`, `String`, `Interactive`
1235 | [Maximum Profit in Job Scheduling](https://leetcode.com/problems/maximum-profit-in-job-scheduling) | Hard | `Array`, `Binary Search`, `Dynamic Programming`, `Sorting`
1234 | [Replace the Substring for Balanced String](https://leetcode.com/problems/replace-the-substring-for-balanced-string) | Medium | `String`, `Sliding Window`
1231 | [Divide Chocolate](https://leetcode.com/problems/divide-chocolate) | Hard | `Array`, `Binary Search`
1230 | [Toss Strange Coins](https://leetcode.com/problems/toss-strange-coins) | Medium | `Math`, `Dynamic Programming`, `Probability and Statistics`
1229 | [Meeting Scheduler](https://leetcode.com/problems/meeting-scheduler) | Medium | `Array`, `Two Pointers`, `Sorting`
1228 | [Missing Number In Arithmetic Progression](https://leetcode.com/problems/missing-number-in-arithmetic-progression) | Easy | `Array`, `Math`
1227 | [Airplane Seat Assignment Probability](https://leetcode.com/problems/airplane-seat-assignment-probability) | Medium | `Brainteaser`, `Math`, `Dynamic Programming`, `Probability and Statistics`
1226 | [The Dining Philosophers](https://leetcode.com/problems/the-dining-philosophers) | Medium | `Concurrency`
1225 | [Report Contiguous Dates](https://leetcode.com/problems/report-contiguous-dates) | Hard | `Database`
1224 | [Maximum Equal Frequency](https://leetcode.com/problems/maximum-equal-frequency) | Hard | `Array`, `Hash Table`
1223 | [Dice Roll Simulation](https://leetcode.com/problems/dice-roll-simulation) | Hard | `Array`, `Dynamic Programming`
1222 | [Queens That Can Attack the King](https://leetcode.com/problems/queens-that-can-attack-the-king) | Medium | `Array`, `Matrix`, `Simulation`
1221 | [Split a String in Balanced Strings](https://leetcode.com/problems/split-a-string-in-balanced-strings) | Easy | `Greedy`, `String`, `Counting`
1220 | [Count Vowels Permutation](https://leetcode.com/problems/count-vowels-permutation) | Hard | `Dynamic Programming`
1219 | [Path with Maximum Gold](https://leetcode.com/problems/path-with-maximum-gold) | Medium | `Array`, `Backtracking`, `Matrix`
1218 | [Longest Arithmetic Subsequence of Given Difference](https://leetcode.com/problems/longest-arithmetic-subsequence-of-given-difference) | Medium | `Array`, `Hash Table`, `Dynamic Programming`
1217 | [Minimum Cost to Move Chips to The Same Position](https://leetcode.com/problems/minimum-cost-to-move-chips-to-the-same-position) | Easy | `Greedy`, `Array`, `Math`
1216 | [Valid Palindrome III](https://leetcode.com/problems/valid-palindrome-iii) | Hard | `String`, `Dynamic Programming`
1215 | [Stepping Numbers](https://leetcode.com/problems/stepping-numbers) | Medium | `Breadth-First Search`, `Backtracking`
1214 | [Two Sum BSTs](https://leetcode.com/problems/two-sum-bsts) | Medium | `Stack`, `Tree`, `Depth-First Search`, `Binary Search Tree`, `Two Pointers`, `Binary Search`, `Binary Tree`
1213 | [Intersection of Three Sorted Arrays](https://leetcode.com/problems/intersection-of-three-sorted-arrays) | Easy | `Array`, `Hash Table`, `Binary Search`, `Counting`
1212 | [Team Scores in Football Tournament](https://leetcode.com/problems/team-scores-in-football-tournament) | Medium | `Database`
1211 | [Queries Quality and Percentage](https://leetcode.com/problems/queries-quality-and-percentage) | Easy | `Database`
1210 | [Minimum Moves to Reach Target with Rotations](https://leetcode.com/problems/minimum-moves-to-reach-target-with-rotations) | Hard | `Breadth-First Search`, `Array`, `Matrix`
1208 | [Get Equal Substrings Within Budget](https://leetcode.com/problems/get-equal-substrings-within-budget) | Medium | `String`, `Binary Search`, `Prefix Sum`, `Sliding Window`
1207 | [Unique Number of Occurrences](https://leetcode.com/problems/unique-number-of-occurrences) | Easy | `Array`, `Hash Table`
1206 | [Design Skiplist](https://leetcode.com/problems/design-skiplist) | Hard | `Design`, `Linked List`
1205 | [Monthly Transactions II](https://leetcode.com/problems/monthly-transactions-ii) | Medium | `Database`
1204 | [Last Person to Fit in the Bus](https://leetcode.com/problems/last-person-to-fit-in-the-bus) | Medium | `Database`
1203 | [Sort Items by Groups Respecting Dependencies](https://leetcode.com/problems/sort-items-by-groups-respecting-dependencies) | Hard | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Topological Sort`
1202 | [Smallest String With Swaps](https://leetcode.com/problems/smallest-string-with-swaps) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Hash Table`, `String`
1201 | [Ugly Number III](https://leetcode.com/problems/ugly-number-iii) | Medium | `Math`, `Binary Search`, `Number Theory`
1200 | [Minimum Absolute Difference](https://leetcode.com/problems/minimum-absolute-difference) | Easy | `Array`, `Sorting`
1199 | [Minimum Time to Build Blocks](https://leetcode.com/problems/minimum-time-to-build-blocks) | Hard | `Greedy`, `Math`, `Heap (Priority Queue)`
1198 | [Find Smallest Common Element in All Rows](https://leetcode.com/problems/find-smallest-common-element-in-all-rows) | Medium | `Array`, `Hash Table`, `Binary Search`, `Counting`, `Matrix`
1197 | [Minimum Knight Moves](https://leetcode.com/problems/minimum-knight-moves) | Medium | `Breadth-First Search`
1196 | [How Many Apples Can You Put into the Basket](https://leetcode.com/problems/how-many-apples-can-you-put-into-the-basket) | Easy | `Greedy`, `Array`, `Sorting`
1195 | [Fizz Buzz Multithreaded](https://leetcode.com/problems/fizz-buzz-multithreaded) | Medium | `Concurrency`
1194 | [Tournament Winners](https://leetcode.com/problems/tournament-winners) | Hard | `Database`
1193 | [Monthly Transactions I](https://leetcode.com/problems/monthly-transactions-i) | Medium | `Database`
1192 | [Critical Connections in a Network](https://leetcode.com/problems/critical-connections-in-a-network) | Hard | `Depth-First Search`, `Graph`, `Biconnected Component`
1191 | [K-Concatenation Maximum Sum](https://leetcode.com/problems/k-concatenation-maximum-sum) | Medium | `Array`, `Dynamic Programming`
1190 | [Reverse Substrings Between Each Pair of Parentheses](https://leetcode.com/problems/reverse-substrings-between-each-pair-of-parentheses) | Medium | `Stack`, `String`
1189 | [Maximum Number of Balloons](https://leetcode.com/problems/maximum-number-of-balloons) | Easy | `Hash Table`, `String`, `Counting`
1188 | [Design Bounded Blocking Queue](https://leetcode.com/problems/design-bounded-blocking-queue) | Medium | `Concurrency`
1187 | [Make Array Strictly Increasing](https://leetcode.com/problems/make-array-strictly-increasing) | Hard | `Array`, `Binary Search`, `Dynamic Programming`
1186 | [Maximum Subarray Sum with One Deletion](https://leetcode.com/problems/maximum-subarray-sum-with-one-deletion) | Medium | `Array`, `Dynamic Programming`
1185 | [Day of the Week](https://leetcode.com/problems/day-of-the-week) | Easy | `Math`
1184 | [Distance Between Bus Stops](https://leetcode.com/problems/distance-between-bus-stops) | Easy | `Array`
1183 | [Maximum Number of Ones](https://leetcode.com/problems/maximum-number-of-ones) | Hard | `Greedy`, `Heap (Priority Queue)`
1182 | [Shortest Distance to Target Color](https://leetcode.com/problems/shortest-distance-to-target-color) | Medium | `Array`, `Binary Search`, `Dynamic Programming`
1181 | [Before and After Puzzle](https://leetcode.com/problems/before-and-after-puzzle) | Medium | `Array`, `Hash Table`, `String`, `Sorting`
1180 | [Count Substrings with Only One Distinct Letter](https://leetcode.com/problems/count-substrings-with-only-one-distinct-letter) | Easy | `Math`, `String`
1179 | [Reformat Department Table](https://leetcode.com/problems/reformat-department-table) | Easy | `Database`
1178 | [Number of Valid Words for Each Puzzle](https://leetcode.com/problems/number-of-valid-words-for-each-puzzle) | Hard | `Bit Manipulation`, `Trie`, `Array`, `Hash Table`, `String`
1177 | [Can Make Palindrome from Substring](https://leetcode.com/problems/can-make-palindrome-from-substring) | Medium | `Bit Manipulation`, `Hash Table`, `String`, `Prefix Sum`
1176 | [Diet Plan Performance](https://leetcode.com/problems/diet-plan-performance) | Easy | `Array`, `Sliding Window`
1175 | [Prime Arrangements](https://leetcode.com/problems/prime-arrangements) | Easy | `Math`
1174 | [Immediate Food Delivery II](https://leetcode.com/problems/immediate-food-delivery-ii) | Medium | `Database`
1173 | [Immediate Food Delivery I](https://leetcode.com/problems/immediate-food-delivery-i) | Easy | `Database`
1172 | [Dinner Plate Stacks](https://leetcode.com/problems/dinner-plate-stacks) | Hard | `Stack`, `Design`, `Hash Table`, `Heap (Priority Queue)`
1171 | [Remove Zero Sum Consecutive Nodes from Linked List](https://leetcode.com/problems/remove-zero-sum-consecutive-nodes-from-linked-list) | Medium | `Hash Table`, `Linked List`
1170 | [Compare Strings by Frequency of the Smallest Character](https://leetcode.com/problems/compare-strings-by-frequency-of-the-smallest-character) | Medium | `Array`, `Hash Table`, `String`, `Binary Search`, `Sorting`
1169 | [Invalid Transactions](https://leetcode.com/problems/invalid-transactions) | Medium | `Array`, `Hash Table`, `String`, `Sorting`
1168 | [Optimize Water Distribution in a Village](https://leetcode.com/problems/optimize-water-distribution-in-a-village) | Hard | `Union Find`, `Graph`, `Minimum Spanning Tree`
1167 | [Minimum Cost to Connect Sticks](https://leetcode.com/problems/minimum-cost-to-connect-sticks) | Medium | `Greedy`, `Array`, `Heap (Priority Queue)`
1166 | [Design File System](https://leetcode.com/problems/design-file-system) | Medium | `Design`, `Trie`, `Hash Table`, `String`
1165 | [Single-Row Keyboard](https://leetcode.com/problems/single-row-keyboard) | Easy | `Hash Table`, `String`
1164 | [Product Price at a Given Date](https://leetcode.com/problems/product-price-at-a-given-date) | Medium | `Database`
1163 | [Last Substring in Lexicographical Order](https://leetcode.com/problems/last-substring-in-lexicographical-order) | Hard | `Two Pointers`, `String`
1162 | [As Far from Land as Possible](https://leetcode.com/problems/as-far-from-land-as-possible) | Medium | `Breadth-First Search`, `Array`, `Dynamic Programming`, `Matrix`
1161 | [Maximum Level Sum of a Binary Tree](https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree) | Medium | `Tree`, `Breadth-First Search`, `Binary Tree`
1160 | [Find Words That Can Be Formed by Characters](https://leetcode.com/problems/find-words-that-can-be-formed-by-characters) | Easy | `Array`, `Hash Table`, `String`
1159 | [Market Analysis II](https://leetcode.com/problems/market-analysis-ii) | Hard | `Database`
1158 | [Market Analysis I](https://leetcode.com/problems/market-analysis-i) | Medium | `Database`
1157 | [Online Majority Element In Subarray](https://leetcode.com/problems/online-majority-element-in-subarray) | Hard | `Design`, `Binary Indexed Tree`, `Segment Tree`, `Array`, `Binary Search`
1156 | [Swap For Longest Repeated Character Substring](https://leetcode.com/problems/swap-for-longest-repeated-character-substring) | Medium | `String`, `Sliding Window`
1155 | [Number of Dice Rolls With Target Sum](https://leetcode.com/problems/number-of-dice-rolls-with-target-sum) | Medium | `Dynamic Programming`
1153 | [String Transforms Into Another String](https://leetcode.com/problems/string-transforms-into-another-string) | Hard | `Hash Table`, `String`
1152 | [Analyze User Website Visit Pattern](https://leetcode.com/problems/analyze-user-website-visit-pattern) | Medium | `Array`, `Hash Table`, `Sorting`
1151 | [Minimum Swaps to Group All 1's Together](https://leetcode.com/problems/minimum-swaps-to-group-all-1s-together) | Medium | `Array`, `Sliding Window`
1150 | [Check If a Number Is Majority Element in a Sorted Array](https://leetcode.com/problems/check-if-a-number-is-majority-element-in-a-sorted-array) | Easy | `Array`, `Binary Search`
1149 | [Article Views II](https://leetcode.com/problems/article-views-ii) | Medium | `Database`
1148 | [Article Views I](https://leetcode.com/problems/article-views-i) | Easy | `Database`
1147 | [Longest Chunked Palindrome Decomposition](https://leetcode.com/problems/longest-chunked-palindrome-decomposition) | Hard | `Greedy`, `Two Pointers`, `String`, `Dynamic Programming`, `Hash Function`, `Rolling Hash`
1145 | [Binary Tree Coloring Game](https://leetcode.com/problems/binary-tree-coloring-game) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1144 | [Decrease Elements To Make Array Zigzag](https://leetcode.com/problems/decrease-elements-to-make-array-zigzag) | Medium | `Greedy`, `Array`
1143 | [Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence) | Medium | `String`, `Dynamic Programming`
1142 | [User Activity for the Past 30 Days II](https://leetcode.com/problems/user-activity-for-the-past-30-days-ii) | Easy | `Database`
1141 | [User Activity for the Past 30 Days I](https://leetcode.com/problems/user-activity-for-the-past-30-days-i) | Easy | `Database`
1140 | [Stone Game II](https://leetcode.com/problems/stone-game-ii) | Medium | `Array`, `Math`, `Dynamic Programming`, `Game Theory`
1139 | [Largest 1-Bordered Square](https://leetcode.com/problems/largest-1-bordered-square) | Medium | `Array`, `Dynamic Programming`, `Matrix`
1138 | [Alphabet Board Path](https://leetcode.com/problems/alphabet-board-path) | Medium | `Hash Table`, `String`
1137 | [N-th Tribonacci Number](https://leetcode.com/problems/n-th-tribonacci-number) | Easy | `Memoization`, `Math`, `Dynamic Programming`
1136 | [Parallel Courses](https://leetcode.com/problems/parallel-courses) | Medium | `Graph`, `Topological Sort`
1135 | [Connecting Cities With Minimum Cost](https://leetcode.com/problems/connecting-cities-with-minimum-cost) | Medium | `Union Find`, `Graph`, `Minimum Spanning Tree`, `Heap (Priority Queue)`
1134 | [Armstrong Number](https://leetcode.com/problems/armstrong-number) | Easy | `Math`
1133 | [Largest Unique Number](https://leetcode.com/problems/largest-unique-number) | Easy | `Array`, `Hash Table`, `Sorting`
1132 | [Reported Posts II](https://leetcode.com/problems/reported-posts-ii) | Medium | `Database`
1130 | [Minimum Cost Tree From Leaf Values](https://leetcode.com/problems/minimum-cost-tree-from-leaf-values) | Medium | `Stack`, `Greedy`, `Dynamic Programming`, `Monotonic Stack`
1129 | [Shortest Path with Alternating Colors](https://leetcode.com/problems/shortest-path-with-alternating-colors) | Medium | `Breadth-First Search`, `Graph`
1127 | [User Purchase Platform](https://leetcode.com/problems/user-purchase-platform) | Hard | `Database`
1126 | [Active Businesses](https://leetcode.com/problems/active-businesses) | Medium | `Database`
1125 | [Smallest Sufficient Team](https://leetcode.com/problems/smallest-sufficient-team) | Hard | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Bitmask`
1124 | [Longest Well-Performing Interval](https://leetcode.com/problems/longest-well-performing-interval) | Medium | `Stack`, `Array`, `Hash Table`, `Prefix Sum`, `Monotonic Stack`
1123 | [Lowest Common Ancestor of Deepest Leaves](https://leetcode.com/problems/lowest-common-ancestor-of-deepest-leaves) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`, `Binary Tree`
1121 | [Divide Array Into Increasing Sequences](https://leetcode.com/problems/divide-array-into-increasing-sequences) | Hard | `Greedy`, `Array`
1120 | [Maximum Average Subtree](https://leetcode.com/problems/maximum-average-subtree) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1119 | [Remove Vowels from a String](https://leetcode.com/problems/remove-vowels-from-a-string) | Easy | `String`
1118 | [Number of Days in a Month](https://leetcode.com/problems/number-of-days-in-a-month) | Easy | `Math`
1117 | [Building H2O](https://leetcode.com/problems/building-h2o) | Medium | `Concurrency`
1116 | [Print Zero Even Odd](https://leetcode.com/problems/print-zero-even-odd) | Medium | `Concurrency`
1115 | [Print FooBar Alternately](https://leetcode.com/problems/print-foobar-alternately) | Medium | `Concurrency`
1114 | [Print in Order](https://leetcode.com/problems/print-in-order) | Easy | `Concurrency`
1113 | [Reported Posts](https://leetcode.com/problems/reported-posts) | Easy | `Database`
1112 | [Highest Grade For Each Student](https://leetcode.com/problems/highest-grade-for-each-student) | Medium | `Database`
1111 | [Maximum Nesting Depth of Two Valid Parentheses Strings](https://leetcode.com/problems/maximum-nesting-depth-of-two-valid-parentheses-strings) | Medium | `Stack`, `String`
1110 | [Delete Nodes And Return Forest](https://leetcode.com/problems/delete-nodes-and-return-forest) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1107 | [New Users Daily Count](https://leetcode.com/problems/new-users-daily-count) | Medium | `Database`
1106 | [Parsing A Boolean Expression](https://leetcode.com/problems/parsing-a-boolean-expression) | Hard | `Stack`, `Recursion`, `String`
1105 | [Filling Bookcase Shelves](https://leetcode.com/problems/filling-bookcase-shelves) | Medium | `Array`, `Dynamic Programming`
1104 | [Path In Zigzag Labelled Binary Tree](https://leetcode.com/problems/path-in-zigzag-labelled-binary-tree) | Medium | `Tree`, `Math`, `Binary Tree`
1103 | [Distribute Candies to People](https://leetcode.com/problems/distribute-candies-to-people) | Easy | `Math`, `Simulation`
1102 | [Path With Maximum Minimum Value](https://leetcode.com/problems/path-with-maximum-minimum-value) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`, `Heap (Priority Queue)`
1101 | [The Earliest Moment When Everyone Become Friends](https://leetcode.com/problems/the-earliest-moment-when-everyone-become-friends) | Medium | `Union Find`, `Array`
1100 | [Find K-Length Substrings With No Repeated Characters](https://leetcode.com/problems/find-k-length-substrings-with-no-repeated-characters) | Medium | `Hash Table`, `String`, `Sliding Window`
1099 | [Two Sum Less Than K](https://leetcode.com/problems/two-sum-less-than-k) | Easy | `Array`, `Two Pointers`, `Binary Search`, `Sorting`
1098 | [Unpopular Books](https://leetcode.com/problems/unpopular-books) | Medium | `Database`
1097 | [Game Play Analysis V](https://leetcode.com/problems/game-play-analysis-v) | Hard | `Database`
1096 | [Brace Expansion II](https://leetcode.com/problems/brace-expansion-ii) | Hard | `Stack`, `Breadth-First Search`, `String`, `Backtracking`
1095 | [Find in Mountain Array](https://leetcode.com/problems/find-in-mountain-array) | Hard | `Array`, `Binary Search`, `Interactive`
1092 | [Shortest Common Supersequence ](https://leetcode.com/problems/shortest-common-supersequence) | Hard | `String`, `Dynamic Programming`
1091 | [Shortest Path in Binary Matrix](https://leetcode.com/problems/shortest-path-in-binary-matrix) | Medium | `Breadth-First Search`, `Array`, `Matrix`
1090 | [Largest Values From Labels](https://leetcode.com/problems/largest-values-from-labels) | Medium | `Greedy`, `Array`, `Hash Table`, `Counting`, `Sorting`
1089 | [Duplicate Zeros](https://leetcode.com/problems/duplicate-zeros) | Easy | `Array`, `Two Pointers`
1088 | [Confusing Number II](https://leetcode.com/problems/confusing-number-ii) | Hard | `Math`, `Backtracking`
1087 | [Brace Expansion](https://leetcode.com/problems/brace-expansion) | Medium | `Breadth-First Search`, `String`, `Backtracking`
1086 | [High Five](https://leetcode.com/problems/high-five) | Easy | `Array`, `Hash Table`, `Sorting`
1085 | [Sum of Digits in the Minimum Number](https://leetcode.com/problems/sum-of-digits-in-the-minimum-number) | Easy | `Array`, `Math`
1084 | [Sales Analysis III](https://leetcode.com/problems/sales-analysis-iii) | Easy | `Database`
1083 | [Sales Analysis II](https://leetcode.com/problems/sales-analysis-ii) | Easy | `Database`
1082 | [Sales Analysis I](https://leetcode.com/problems/sales-analysis-i) | Easy | `Database`
1081 | [Smallest Subsequence of Distinct Characters](https://leetcode.com/problems/smallest-subsequence-of-distinct-characters) | Medium | `Stack`, `Greedy`, `String`, `Monotonic Stack`
1080 | [Insufficient Nodes in Root to Leaf Paths](https://leetcode.com/problems/insufficient-nodes-in-root-to-leaf-paths) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1079 | [Letter Tile Possibilities](https://leetcode.com/problems/letter-tile-possibilities) | Medium | `String`, `Backtracking`
1078 | [Occurrences After Bigram](https://leetcode.com/problems/occurrences-after-bigram) | Easy | `String`
1077 | [Project Employees III](https://leetcode.com/problems/project-employees-iii) | Medium | `Database`
1076 | [Project Employees II](https://leetcode.com/problems/project-employees-ii) | Easy | `Database`
1075 | [Project Employees I](https://leetcode.com/problems/project-employees-i) | Easy | `Database`
1074 | [Number of Submatrices That Sum to Target](https://leetcode.com/problems/number-of-submatrices-that-sum-to-target) | Hard | `Array`, `Hash Table`, `Matrix`, `Prefix Sum`
1073 | [Adding Two Negabinary Numbers](https://leetcode.com/problems/adding-two-negabinary-numbers) | Medium | `Array`, `Math`
1072 | [Flip Columns For Maximum Number of Equal Rows](https://leetcode.com/problems/flip-columns-for-maximum-number-of-equal-rows) | Medium | `Array`, `Hash Table`, `Matrix`
1071 | [Greatest Common Divisor of Strings](https://leetcode.com/problems/greatest-common-divisor-of-strings) | Easy | `Math`, `String`
1070 | [Product Sales Analysis III](https://leetcode.com/problems/product-sales-analysis-iii) | Medium | `Database`
1069 | [Product Sales Analysis II](https://leetcode.com/problems/product-sales-analysis-ii) | Easy | `Database`
1068 | [Product Sales Analysis I](https://leetcode.com/problems/product-sales-analysis-i) | Easy | `Database`
1067 | [Digit Count in Range](https://leetcode.com/problems/digit-count-in-range) | Hard | `Math`, `Dynamic Programming`
1066 | [Campus Bikes II](https://leetcode.com/problems/campus-bikes-ii) | Medium | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
1065 | [Index Pairs of a String](https://leetcode.com/problems/index-pairs-of-a-string) | Easy | `Trie`, `Array`, `String`, `Sorting`
1064 | [Fixed Point](https://leetcode.com/problems/fixed-point) | Easy | `Array`, `Binary Search`
1063 | [Number of Valid Subarrays](https://leetcode.com/problems/number-of-valid-subarrays) | Hard | `Stack`, `Array`, `Monotonic Stack`
1062 | [Longest Repeating Substring](https://leetcode.com/problems/longest-repeating-substring) | Medium | `String`, `Binary Search`, `Dynamic Programming`, `Suffix Array`, `Hash Function`, `Rolling Hash`
1061 | [Lexicographically Smallest Equivalent String](https://leetcode.com/problems/lexicographically-smallest-equivalent-string) | Medium | `Union Find`, `String`
1060 | [Missing Element in Sorted Array](https://leetcode.com/problems/missing-element-in-sorted-array) | Medium | `Array`, `Binary Search`
1059 | [All Paths from Source Lead to Destination](https://leetcode.com/problems/all-paths-from-source-lead-to-destination) | Medium | `Depth-First Search`, `Graph`
1058 | [Minimize Rounding Error to Meet Target](https://leetcode.com/problems/minimize-rounding-error-to-meet-target) | Medium | `Greedy`, `Array`, `Math`, `String`
1057 | [Campus Bikes](https://leetcode.com/problems/campus-bikes) | Medium | `Greedy`, `Array`, `Sorting`
1056 | [Confusing Number](https://leetcode.com/problems/confusing-number) | Easy | `Math`
1055 | [Shortest Way to Form String](https://leetcode.com/problems/shortest-way-to-form-string) | Medium | `Greedy`, `String`, `Dynamic Programming`
1054 | [Distant Barcodes](https://leetcode.com/problems/distant-barcodes) | Medium | `Greedy`, `Array`, `Hash Table`, `Counting`, `Sorting`, `Heap (Priority Queue)`
1053 | [Previous Permutation With One Swap](https://leetcode.com/problems/previous-permutation-with-one-swap) | Medium | `Greedy`, `Array`
1052 | [Grumpy Bookstore Owner](https://leetcode.com/problems/grumpy-bookstore-owner) | Medium | `Array`, `Sliding Window`
1051 | [Height Checker](https://leetcode.com/problems/height-checker) | Easy | `Array`, `Counting Sort`, `Sorting`
1050 | [Actors and Directors Who Cooperated At Least Three Times](https://leetcode.com/problems/actors-and-directors-who-cooperated-at-least-three-times) | Easy | `Database`
1049 | [Last Stone Weight II](https://leetcode.com/problems/last-stone-weight-ii) | Medium | `Array`, `Dynamic Programming`
1048 | [Longest String Chain](https://leetcode.com/problems/longest-string-chain) | Medium | `Array`, `Hash Table`, `Two Pointers`, `String`, `Dynamic Programming`
1045 | [Customers Who Bought All Products](https://leetcode.com/problems/customers-who-bought-all-products) | Medium | `Database`
1044 | [Longest Duplicate Substring](https://leetcode.com/problems/longest-duplicate-substring) | Hard | `String`, `Binary Search`, `Suffix Array`, `Sliding Window`, `Hash Function`, `Rolling Hash`
1043 | [Partition Array for Maximum Sum](https://leetcode.com/problems/partition-array-for-maximum-sum) | Medium | `Array`, `Dynamic Programming`
1042 | [Flower Planting With No Adjacent](https://leetcode.com/problems/flower-planting-with-no-adjacent) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`
1041 | [Robot Bounded In Circle](https://leetcode.com/problems/robot-bounded-in-circle) | Medium | `Math`, `String`, `Simulation`
1040 | [Moving Stones Until Consecutive II](https://leetcode.com/problems/moving-stones-until-consecutive-ii) | Medium | `Array`, `Math`, `Two Pointers`, `Sorting`
1039 | [Minimum Score Triangulation of Polygon](https://leetcode.com/problems/minimum-score-triangulation-of-polygon) | Medium | `Array`, `Dynamic Programming`
1038 | [Binary Search Tree to Greater Sum Tree](https://leetcode.com/problems/binary-search-tree-to-greater-sum-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
1037 | [Valid Boomerang](https://leetcode.com/problems/valid-boomerang) | Easy | `Geometry`, `Math`
1036 | [Escape a Large Maze](https://leetcode.com/problems/escape-a-large-maze) | Hard | `Depth-First Search`, `Breadth-First Search`, `Array`, `Hash Table`
1035 | [Uncrossed Lines](https://leetcode.com/problems/uncrossed-lines) | Medium | `Array`, `Dynamic Programming`
1034 | [Coloring A Border](https://leetcode.com/problems/coloring-a-border) | Medium | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`
1033 | [Moving Stones Until Consecutive](https://leetcode.com/problems/moving-stones-until-consecutive) | Medium | `Brainteaser`, `Math`
1032 | [Stream of Characters](https://leetcode.com/problems/stream-of-characters) | Hard | `Design`, `Trie`, `Array`, `String`, `Data Stream`
1031 | [Maximum Sum of Two Non-Overlapping Subarrays](https://leetcode.com/problems/maximum-sum-of-two-non-overlapping-subarrays) | Medium | `Array`, `Dynamic Programming`, `Sliding Window`
1029 | [Two City Scheduling](https://leetcode.com/problems/two-city-scheduling) | Medium | `Greedy`, `Array`, `Sorting`
1028 | [Recover a Tree From Preorder Traversal](https://leetcode.com/problems/recover-a-tree-from-preorder-traversal) | Hard | `Tree`, `Depth-First Search`, `String`, `Binary Tree`
1027 | [Longest Arithmetic Subsequence](https://leetcode.com/problems/longest-arithmetic-subsequence) | Medium | `Array`, `Hash Table`, `Binary Search`, `Dynamic Programming`
1026 | [Maximum Difference Between Node and Ancestor](https://leetcode.com/problems/maximum-difference-between-node-and-ancestor) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
1025 | [Divisor Game](https://leetcode.com/problems/divisor-game) | Easy | `Brainteaser`, `Math`, `Dynamic Programming`, `Game Theory`
1024 | [Video Stitching](https://leetcode.com/problems/video-stitching) | Medium | `Greedy`, `Array`, `Dynamic Programming`
1023 | [Camelcase Matching](https://leetcode.com/problems/camelcase-matching) | Medium | `Trie`, `Two Pointers`, `String`, `String Matching`
1022 | [Sum of Root To Leaf Binary Numbers](https://leetcode.com/problems/sum-of-root-to-leaf-binary-numbers) | Easy | `Tree`, `Depth-First Search`, `Binary Tree`
1021 | [Remove Outermost Parentheses](https://leetcode.com/problems/remove-outermost-parentheses) | Easy | `Stack`, `String`
1020 | [Number of Enclaves](https://leetcode.com/problems/number-of-enclaves) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
1019 | [Next Greater Node In Linked List](https://leetcode.com/problems/next-greater-node-in-linked-list) | Medium | `Stack`, `Array`, `Linked List`, `Monotonic Stack`
1018 | [Binary Prefix Divisible By 5](https://leetcode.com/problems/binary-prefix-divisible-by-5) | Easy | `Array`
1017 | [Convert to Base -2](https://leetcode.com/problems/convert-to-base-2) | Medium | `Math`
1016 | [Binary String With Substrings Representing 1 To N](https://leetcode.com/problems/binary-string-with-substrings-representing-1-to-n) | Medium | `String`
1015 | [Smallest Integer Divisible by K](https://leetcode.com/problems/smallest-integer-divisible-by-k) | Medium | `Hash Table`, `Math`
1013 | [Partition Array Into Three Parts With Equal Sum](https://leetcode.com/problems/partition-array-into-three-parts-with-equal-sum) | Easy | `Greedy`, `Array`
1012 | [Numbers With Repeated Digits](https://leetcode.com/problems/numbers-with-repeated-digits) | Hard | `Math`, `Dynamic Programming`
1011 | [Capacity To Ship Packages Within D Days](https://leetcode.com/problems/capacity-to-ship-packages-within-d-days) | Medium | `Greedy`, `Array`, `Binary Search`
1010 | [Pairs of Songs With Total Durations Divisible by 60](https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60) | Medium | `Array`, `Hash Table`, `Counting`
1007 | [Minimum Domino Rotations For Equal Row](https://leetcode.com/problems/minimum-domino-rotations-for-equal-row) | Medium | `Greedy`, `Array`
1006 | [Clumsy Factorial](https://leetcode.com/problems/clumsy-factorial) | Medium | `Stack`, `Math`, `Simulation`
1005 | [Maximize Sum Of Array After K Negations](https://leetcode.com/problems/maximize-sum-of-array-after-k-negations) | Easy | `Greedy`, `Array`, `Sorting`
1004 | [Max Consecutive Ones III](https://leetcode.com/problems/max-consecutive-ones-iii) | Medium | `Array`, `Binary Search`, `Prefix Sum`, `Sliding Window`
1003 | [Check If Word Is Valid After Substitutions](https://leetcode.com/problems/check-if-word-is-valid-after-substitutions) | Medium | `Stack`, `String`
1002 | [Find Common Characters](https://leetcode.com/problems/find-common-characters) | Easy | `Array`, `Hash Table`, `String`
1001 | [Grid Illumination](https://leetcode.com/problems/grid-illumination) | Hard | `Array`, `Hash Table`
1000 | [Minimum Cost to Merge Stones](https://leetcode.com/problems/minimum-cost-to-merge-stones) | Hard | `Array`, `Dynamic Programming`
999 | [Available Captures for Rook](https://leetcode.com/problems/available-captures-for-rook) | Easy | `Array`, `Matrix`, `Simulation`
998 | [Maximum Binary Tree II](https://leetcode.com/problems/maximum-binary-tree-ii) | Medium | `Tree`, `Binary Tree`
997 | [Find the Town Judge](https://leetcode.com/problems/find-the-town-judge) | Easy | `Graph`, `Array`, `Hash Table`
996 | [Number of Squareful Arrays](https://leetcode.com/problems/number-of-squareful-arrays) | Hard | `Bit Manipulation`, `Array`, `Math`, `Dynamic Programming`, `Backtracking`, `Bitmask`
995 | [Minimum Number of K Consecutive Bit Flips](https://leetcode.com/problems/minimum-number-of-k-consecutive-bit-flips) | Hard | `Bit Manipulation`, `Array`, `Prefix Sum`, `Sliding Window`
994 | [Rotting Oranges](https://leetcode.com/problems/rotting-oranges) | Medium | `Breadth-First Search`, `Array`, `Matrix`
993 | [Cousins in Binary Tree](https://leetcode.com/problems/cousins-in-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
992 | [Subarrays with K Different Integers](https://leetcode.com/problems/subarrays-with-k-different-integers) | Hard | `Array`, `Hash Table`, `Counting`, `Sliding Window`
991 | [Broken Calculator](https://leetcode.com/problems/broken-calculator) | Medium | `Greedy`, `Math`
989 | [Add to Array-Form of Integer](https://leetcode.com/problems/add-to-array-form-of-integer) | Easy | `Array`, `Math`
988 | [Smallest String Starting From Leaf](https://leetcode.com/problems/smallest-string-starting-from-leaf) | Medium | `Tree`, `Depth-First Search`, `String`, `Binary Tree`
987 | [Vertical Order Traversal of a Binary Tree](https://leetcode.com/problems/vertical-order-traversal-of-a-binary-tree) | Hard | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`, `Binary Tree`
986 | [Interval List Intersections](https://leetcode.com/problems/interval-list-intersections) | Medium | `Array`, `Two Pointers`
985 | [Sum of Even Numbers After Queries](https://leetcode.com/problems/sum-of-even-numbers-after-queries) | Medium | `Array`, `Simulation`
984 | [String Without AAA or BBB](https://leetcode.com/problems/string-without-aaa-or-bbb) | Medium | `Greedy`, `String`
983 | [Minimum Cost For Tickets](https://leetcode.com/problems/minimum-cost-for-tickets) | Medium | `Array`, `Dynamic Programming`
982 | [Triples with Bitwise AND Equal To Zero](https://leetcode.com/problems/triples-with-bitwise-and-equal-to-zero) | Hard | `Bit Manipulation`, `Array`, `Hash Table`
981 | [Time Based Key-Value Store](https://leetcode.com/problems/time-based-key-value-store) | Medium | `Design`, `Hash Table`, `String`, `Binary Search`
980 | [Unique Paths III](https://leetcode.com/problems/unique-paths-iii) | Hard | `Bit Manipulation`, `Array`, `Backtracking`, `Matrix`
979 | [Distribute Coins in Binary Tree](https://leetcode.com/problems/distribute-coins-in-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
978 | [Longest Turbulent Subarray](https://leetcode.com/problems/longest-turbulent-subarray) | Medium | `Array`, `Dynamic Programming`, `Sliding Window`
977 | [Squares of a Sorted Array](https://leetcode.com/problems/squares-of-a-sorted-array) | Easy | `Array`, `Two Pointers`, `Sorting`
976 | [Largest Perimeter Triangle](https://leetcode.com/problems/largest-perimeter-triangle) | Easy | `Greedy`, `Array`, `Math`, `Sorting`
975 | [Odd Even Jump](https://leetcode.com/problems/odd-even-jump) | Hard | `Stack`, `Array`, `Dynamic Programming`, `Ordered Set`, `Monotonic Stack`
974 | [Subarray Sums Divisible by K](https://leetcode.com/problems/subarray-sums-divisible-by-k) | Medium | `Array`, `Hash Table`, `Prefix Sum`
972 | [Equal Rational Numbers](https://leetcode.com/problems/equal-rational-numbers) | Hard | `Math`, `String`
971 | [Flip Binary Tree To Match Preorder Traversal](https://leetcode.com/problems/flip-binary-tree-to-match-preorder-traversal) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
970 | [Powerful Integers](https://leetcode.com/problems/powerful-integers) | Medium | `Hash Table`, `Math`
969 | [Pancake Sorting](https://leetcode.com/problems/pancake-sorting) | Medium | `Greedy`, `Array`, `Two Pointers`, `Sorting`
968 | [Binary Tree Cameras](https://leetcode.com/problems/binary-tree-cameras) | Hard | `Tree`, `Depth-First Search`, `Dynamic Programming`, `Binary Tree`
967 | [Numbers With Same Consecutive Differences](https://leetcode.com/problems/numbers-with-same-consecutive-differences) | Medium | `Breadth-First Search`, `Backtracking`
966 | [Vowel Spellchecker](https://leetcode.com/problems/vowel-spellchecker) | Medium | `Array`, `Hash Table`, `String`
965 | [Univalued Binary Tree](https://leetcode.com/problems/univalued-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
964 | [Least Operators to Express Number](https://leetcode.com/problems/least-operators-to-express-number) | Hard | `Math`, `Dynamic Programming`
963 | [Minimum Area Rectangle II](https://leetcode.com/problems/minimum-area-rectangle-ii) | Medium | `Geometry`, `Array`, `Math`
962 | [Maximum Width Ramp](https://leetcode.com/problems/maximum-width-ramp) | Medium | `Stack`, `Array`, `Monotonic Stack`
960 | [Delete Columns to Make Sorted III](https://leetcode.com/problems/delete-columns-to-make-sorted-iii) | Hard | `Array`, `String`, `Dynamic Programming`
959 | [Regions Cut By Slashes](https://leetcode.com/problems/regions-cut-by-slashes) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
958 | [Check Completeness of a Binary Tree](https://leetcode.com/problems/check-completeness-of-a-binary-tree) | Medium | `Tree`, `Breadth-First Search`, `Binary Tree`
956 | [Tallest Billboard](https://leetcode.com/problems/tallest-billboard) | Hard | `Array`, `Dynamic Programming`
955 | [Delete Columns to Make Sorted II](https://leetcode.com/problems/delete-columns-to-make-sorted-ii) | Medium | `Greedy`, `Array`, `String`
954 | [Array of Doubled Pairs](https://leetcode.com/problems/array-of-doubled-pairs) | Medium | `Greedy`, `Array`, `Hash Table`, `Sorting`
953 | [Verifying an Alien Dictionary](https://leetcode.com/problems/verifying-an-alien-dictionary) | Easy | `Array`, `Hash Table`, `String`
952 | [Largest Component Size by Common Factor](https://leetcode.com/problems/largest-component-size-by-common-factor) | Hard | `Union Find`, `Array`, `Math`
951 | [Flip Equivalent Binary Trees](https://leetcode.com/problems/flip-equivalent-binary-trees) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
950 | [Reveal Cards In Increasing Order](https://leetcode.com/problems/reveal-cards-in-increasing-order) | Medium | `Queue`, `Array`, `Sorting`, `Simulation`
949 | [Largest Time for Given Digits](https://leetcode.com/problems/largest-time-for-given-digits) | Medium | `String`, `Enumeration`
948 | [Bag of Tokens](https://leetcode.com/problems/bag-of-tokens) | Medium | `Greedy`, `Array`, `Two Pointers`, `Sorting`
947 | [Most Stones Removed with Same Row or Column](https://leetcode.com/problems/most-stones-removed-with-same-row-or-column) | Medium | `Depth-First Search`, `Union Find`, `Graph`
946 | [Validate Stack Sequences](https://leetcode.com/problems/validate-stack-sequences) | Medium | `Stack`, `Array`, `Simulation`
945 | [Minimum Increment to Make Array Unique](https://leetcode.com/problems/minimum-increment-to-make-array-unique) | Medium | `Greedy`, `Array`, `Counting`, `Sorting`
944 | [Delete Columns to Make Sorted](https://leetcode.com/problems/delete-columns-to-make-sorted) | Easy | `Array`, `String`
943 | [Find the Shortest Superstring](https://leetcode.com/problems/find-the-shortest-superstring) | Hard | `Bit Manipulation`, `Array`, `String`, `Dynamic Programming`, `Bitmask`
942 | [DI String Match](https://leetcode.com/problems/di-string-match) | Easy | `Greedy`, `Array`, `Math`, `Two Pointers`, `String`
941 | [Valid Mountain Array](https://leetcode.com/problems/valid-mountain-array) | Easy | `Array`
940 | [Distinct Subsequences II](https://leetcode.com/problems/distinct-subsequences-ii) | Hard | `String`, `Dynamic Programming`
939 | [Minimum Area Rectangle](https://leetcode.com/problems/minimum-area-rectangle) | Medium | `Geometry`, `Array`, `Hash Table`, `Math`, `Sorting`
938 | [Range Sum of BST](https://leetcode.com/problems/range-sum-of-bst) | Easy | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
937 | [Reorder Data in Log Files](https://leetcode.com/problems/reorder-data-in-log-files) | Easy | `Array`, `String`, `Sorting`
936 | [Stamping The Sequence](https://leetcode.com/problems/stamping-the-sequence) | Hard | `Stack`, `Greedy`, `Queue`, `String`
935 | [Knight Dialer](https://leetcode.com/problems/knight-dialer) | Medium | `Dynamic Programming`
934 | [Shortest Bridge](https://leetcode.com/problems/shortest-bridge) | Medium | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`
933 | [Number of Recent Calls](https://leetcode.com/problems/number-of-recent-calls) | Easy | `Design`, `Queue`, `Data Stream`
932 | [Beautiful Array](https://leetcode.com/problems/beautiful-array) | Medium | `Array`, `Math`, `Divide and Conquer`
931 | [Minimum Falling Path Sum](https://leetcode.com/problems/minimum-falling-path-sum) | Medium | `Array`, `Dynamic Programming`, `Matrix`
930 | [Binary Subarrays With Sum](https://leetcode.com/problems/binary-subarrays-with-sum) | Medium | `Array`, `Hash Table`, `Prefix Sum`, `Sliding Window`
929 | [Unique Email Addresses](https://leetcode.com/problems/unique-email-addresses) | Easy | `Array`, `Hash Table`, `String`
928 | [Minimize Malware Spread II](https://leetcode.com/problems/minimize-malware-spread-ii) | Hard | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
927 | [Three Equal Parts](https://leetcode.com/problems/three-equal-parts) | Hard | `Array`, `Math`
926 | [Flip String to Monotone Increasing](https://leetcode.com/problems/flip-string-to-monotone-increasing) | Medium | `String`, `Dynamic Programming`
925 | [Long Pressed Name](https://leetcode.com/problems/long-pressed-name) | Easy | `Two Pointers`, `String`
924 | [Minimize Malware Spread](https://leetcode.com/problems/minimize-malware-spread) | Hard | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
923 | [3Sum With Multiplicity](https://leetcode.com/problems/3sum-with-multiplicity) | Medium | `Array`, `Hash Table`, `Two Pointers`, `Counting`, `Sorting`
922 | [Sort Array By Parity II](https://leetcode.com/problems/sort-array-by-parity-ii) | Easy | `Array`, `Two Pointers`, `Sorting`
921 | [Minimum Add to Make Parentheses Valid](https://leetcode.com/problems/minimum-add-to-make-parentheses-valid) | Medium | `Stack`, `Greedy`, `String`
920 | [Number of Music Playlists](https://leetcode.com/problems/number-of-music-playlists) | Hard | `Math`, `Dynamic Programming`, `Combinatorics`
919 | [Complete Binary Tree Inserter](https://leetcode.com/problems/complete-binary-tree-inserter) | Medium | `Tree`, `Breadth-First Search`, `Design`, `Binary Tree`
918 | [Maximum Sum Circular Subarray](https://leetcode.com/problems/maximum-sum-circular-subarray) | Medium | `Queue`, `Array`, `Divide and Conquer`, `Dynamic Programming`, `Monotonic Queue`
915 | [Partition Array into Disjoint Intervals](https://leetcode.com/problems/partition-array-into-disjoint-intervals) | Medium | `Array`
914 | [X of a Kind in a Deck of Cards](https://leetcode.com/problems/x-of-a-kind-in-a-deck-of-cards) | Easy | `Array`, `Hash Table`, `Math`, `Counting`, `Number Theory`
913 | [Cat and Mouse](https://leetcode.com/problems/cat-and-mouse) | Hard | `Breadth-First Search`, `Graph`, `Memoization`, `Math`, `Dynamic Programming`, `Game Theory`
912 | [Sort an Array](https://leetcode.com/problems/sort-an-array) | Medium | `Array`, `Divide and Conquer`, `Bucket Sort`, `Counting Sort`, `Radix Sort`, `Sorting`, `Heap (Priority Queue)`, `Merge Sort`
911 | [Online Election](https://leetcode.com/problems/online-election) | Medium | `Design`, `Array`, `Hash Table`, `Binary Search`
910 | [Smallest Range II](https://leetcode.com/problems/smallest-range-ii) | Medium | `Greedy`, `Array`, `Math`, `Sorting`
909 | [Snakes and Ladders](https://leetcode.com/problems/snakes-and-ladders) | Medium | `Breadth-First Search`, `Array`, `Matrix`
908 | [Smallest Range I](https://leetcode.com/problems/smallest-range-i) | Easy | `Array`, `Math`
907 | [Sum of Subarray Minimums](https://leetcode.com/problems/sum-of-subarray-minimums) | Medium | `Stack`, `Array`, `Dynamic Programming`, `Monotonic Stack`
906 | [Super Palindromes](https://leetcode.com/problems/super-palindromes) | Hard | `Math`, `Enumeration`
904 | [Fruit Into Baskets](https://leetcode.com/problems/fruit-into-baskets) | Medium | `Array`, `Hash Table`, `Sliding Window`
903 | [Valid Permutations for DI Sequence](https://leetcode.com/problems/valid-permutations-for-di-sequence) | Hard | `Dynamic Programming`
902 | [Numbers At Most N Given Digit Set](https://leetcode.com/problems/numbers-at-most-n-given-digit-set) | Hard | `Array`, `Math`, `Binary Search`, `Dynamic Programming`
901 | [Online Stock Span](https://leetcode.com/problems/online-stock-span) | Medium | `Stack`, `Design`, `Data Stream`, `Monotonic Stack`
900 | [RLE Iterator](https://leetcode.com/problems/rle-iterator) | Medium | `Design`, `Array`, `Counting`, `Iterator`
899 | [Orderly Queue](https://leetcode.com/problems/orderly-queue) | Hard | `Math`, `String`, `Sorting`
898 | [Bitwise ORs of Subarrays](https://leetcode.com/problems/bitwise-ors-of-subarrays) | Medium | `Bit Manipulation`, `Array`, `Dynamic Programming`
897 | [Increasing Order Search Tree](https://leetcode.com/problems/increasing-order-search-tree) | Easy | `Stack`, `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
896 | [Monotonic Array](https://leetcode.com/problems/monotonic-array) | Easy | `Array`
895 | [Maximum Frequency Stack](https://leetcode.com/problems/maximum-frequency-stack) | Hard | `Stack`, `Design`, `Hash Table`, `Ordered Set`
894 | [All Possible Full Binary Trees](https://leetcode.com/problems/all-possible-full-binary-trees) | Medium | `Tree`, `Recursion`, `Memoization`, `Dynamic Programming`, `Binary Tree`
893 | [Groups of Special-Equivalent Strings](https://leetcode.com/problems/groups-of-special-equivalent-strings) | Medium | `Array`, `Hash Table`, `String`
892 | [Surface Area of 3D Shapes](https://leetcode.com/problems/surface-area-of-3d-shapes) | Easy | `Geometry`, `Array`, `Math`, `Matrix`
891 | [Sum of Subsequence Widths](https://leetcode.com/problems/sum-of-subsequence-widths) | Hard | `Array`, `Math`, `Sorting`
890 | [Find and Replace Pattern](https://leetcode.com/problems/find-and-replace-pattern) | Medium | `Array`, `Hash Table`, `String`
889 | [Construct Binary Tree from Preorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-postorder-traversal) | Medium | `Tree`, `Array`, `Hash Table`, `Divide and Conquer`, `Binary Tree`
888 | [Fair Candy Swap](https://leetcode.com/problems/fair-candy-swap) | Easy | `Array`, `Hash Table`, `Binary Search`, `Sorting`
887 | [Super Egg Drop](https://leetcode.com/problems/super-egg-drop) | Hard | `Math`, `Binary Search`, `Dynamic Programming`
886 | [Possible Bipartition](https://leetcode.com/problems/possible-bipartition) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
885 | [Spiral Matrix III](https://leetcode.com/problems/spiral-matrix-iii) | Medium | `Array`, `Matrix`, `Simulation`
884 | [Uncommon Words from Two Sentences](https://leetcode.com/problems/uncommon-words-from-two-sentences) | Easy | `Hash Table`, `String`
883 | [Projection Area of 3D Shapes](https://leetcode.com/problems/projection-area-of-3d-shapes) | Easy | `Geometry`, `Array`, `Math`, `Matrix`
882 | [Reachable Nodes In Subdivided Graph](https://leetcode.com/problems/reachable-nodes-in-subdivided-graph) | Hard | `Graph`, `Shortest Path`, `Heap (Priority Queue)`
881 | [Boats to Save People](https://leetcode.com/problems/boats-to-save-people) | Medium | `Greedy`, `Array`, `Two Pointers`, `Sorting`
880 | [Decoded String at Index](https://leetcode.com/problems/decoded-string-at-index) | Medium | `Stack`, `String`
879 | [Profitable Schemes](https://leetcode.com/problems/profitable-schemes) | Hard | `Array`, `Dynamic Programming`
878 | [Nth Magical Number](https://leetcode.com/problems/nth-magical-number) | Hard | `Math`, `Binary Search`
877 | [Stone Game](https://leetcode.com/problems/stone-game) | Medium | `Array`, `Math`, `Dynamic Programming`, `Game Theory`
876 | [Middle of the Linked List](https://leetcode.com/problems/middle-of-the-linked-list) | Easy | `Linked List`, `Two Pointers`
875 | [Koko Eating Bananas](https://leetcode.com/problems/koko-eating-bananas) | Medium | `Array`, `Binary Search`
874 | [Walking Robot Simulation](https://leetcode.com/problems/walking-robot-simulation) | Medium | `Array`, `Simulation`
873 | [Length of Longest Fibonacci Subsequence](https://leetcode.com/problems/length-of-longest-fibonacci-subsequence) | Medium | `Array`, `Hash Table`, `Dynamic Programming`
872 | [Leaf-Similar Trees](https://leetcode.com/problems/leaf-similar-trees) | Easy | `Tree`, `Depth-First Search`, `Binary Tree`
871 | [Minimum Number of Refueling Stops](https://leetcode.com/problems/minimum-number-of-refueling-stops) | Hard | `Greedy`, `Array`, `Dynamic Programming`, `Heap (Priority Queue)`
870 | [Advantage Shuffle](https://leetcode.com/problems/advantage-shuffle) | Medium | `Greedy`, `Array`, `Sorting`
869 | [Reordered Power of 2](https://leetcode.com/problems/reordered-power-of-2) | Medium | `Math`, `Counting`, `Enumeration`, `Sorting`
868 | [Binary Gap](https://leetcode.com/problems/binary-gap) | Easy | `Bit Manipulation`, `Math`
867 | [Transpose Matrix](https://leetcode.com/problems/transpose-matrix) | Easy | `Array`, `Matrix`, `Simulation`
866 | [Prime Palindrome](https://leetcode.com/problems/prime-palindrome) | Medium | `Math`
865 | [Smallest Subtree with all the Deepest Nodes](https://leetcode.com/problems/smallest-subtree-with-all-the-deepest-nodes) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`, `Binary Tree`
864 | [Shortest Path to Get All Keys](https://leetcode.com/problems/shortest-path-to-get-all-keys) | Hard | `Bit Manipulation`, `Breadth-First Search`
863 | [All Nodes Distance K in Binary Tree](https://leetcode.com/problems/all-nodes-distance-k-in-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
862 | [Shortest Subarray with Sum at Least K](https://leetcode.com/problems/shortest-subarray-with-sum-at-least-k) | Hard | `Queue`, `Array`, `Binary Search`, `Prefix Sum`, `Sliding Window`, `Monotonic Queue`, `Heap (Priority Queue)`
861 | [Score After Flipping Matrix](https://leetcode.com/problems/score-after-flipping-matrix) | Medium | `Greedy`, `Bit Manipulation`, `Array`, `Matrix`
860 | [Lemonade Change](https://leetcode.com/problems/lemonade-change) | Easy | `Greedy`, `Array`
859 | [Buddy Strings](https://leetcode.com/problems/buddy-strings) | Easy | `Hash Table`, `String`
858 | [Mirror Reflection](https://leetcode.com/problems/mirror-reflection) | Medium | `Geometry`, `Math`
857 | [Minimum Cost to Hire K Workers](https://leetcode.com/problems/minimum-cost-to-hire-k-workers) | Hard | `Greedy`, `Array`, `Sorting`, `Heap (Priority Queue)`
856 | [Score of Parentheses](https://leetcode.com/problems/score-of-parentheses) | Medium | `Stack`, `String`
855 | [Exam Room](https://leetcode.com/problems/exam-room) | Medium | `Design`, `Ordered Set`
854 | [K-Similar Strings](https://leetcode.com/problems/k-similar-strings) | Hard | `Breadth-First Search`, `String`
853 | [Car Fleet](https://leetcode.com/problems/car-fleet) | Medium | `Array`, `Sorting`
852 | [Peak Index in a Mountain Array](https://leetcode.com/problems/peak-index-in-a-mountain-array) | Easy | `Array`, `Binary Search`
851 | [Loud and Rich](https://leetcode.com/problems/loud-and-rich) | Medium | `Depth-First Search`, `Graph`, `Topological Sort`, `Array`
850 | [Rectangle Area II](https://leetcode.com/problems/rectangle-area-ii) | Hard | `Segment Tree`, `Array`, `Ordered Set`, `Line Sweep`
849 | [Maximize Distance to Closest Person](https://leetcode.com/problems/maximize-distance-to-closest-person) | Medium | `Array`
847 | [Shortest Path Visiting All Nodes](https://leetcode.com/problems/shortest-path-visiting-all-nodes) | Hard | `Bit Manipulation`, `Breadth-First Search`, `Graph`, `Dynamic Programming`, `Bitmask`
846 | [Hand of Straights](https://leetcode.com/problems/hand-of-straights) | Medium | `Greedy`, `Array`, `Hash Table`, `Sorting`
845 | [Longest Mountain in Array](https://leetcode.com/problems/longest-mountain-in-array) | Medium | `Array`, `Two Pointers`, `Dynamic Programming`, `Enumeration`
844 | [Backspace String Compare](https://leetcode.com/problems/backspace-string-compare) | Easy | `Stack`, `Two Pointers`, `String`, `Simulation`
843 | [Guess the Word](https://leetcode.com/problems/guess-the-word) | Hard | `Array`, `Math`, `String`, `Game Theory`, `Interactive`
842 | [Split Array into Fibonacci Sequence](https://leetcode.com/problems/split-array-into-fibonacci-sequence) | Medium | `String`, `Backtracking`
841 | [Keys and Rooms](https://leetcode.com/problems/keys-and-rooms) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`
840 | [Magic Squares In Grid](https://leetcode.com/problems/magic-squares-in-grid) | Medium | `Array`, `Math`, `Matrix`
839 | [Similar String Groups](https://leetcode.com/problems/similar-string-groups) | Hard | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `String`
838 | [Push Dominoes](https://leetcode.com/problems/push-dominoes) | Medium | `Two Pointers`, `String`, `Dynamic Programming`
837 | [New 21 Game](https://leetcode.com/problems/new-21-game) | Medium | `Math`, `Dynamic Programming`, `Sliding Window`, `Probability and Statistics`
836 | [Rectangle Overlap](https://leetcode.com/problems/rectangle-overlap) | Easy | `Geometry`, `Math`
835 | [Image Overlap](https://leetcode.com/problems/image-overlap) | Medium | `Array`, `Matrix`
834 | [Sum of Distances in Tree](https://leetcode.com/problems/sum-of-distances-in-tree) | Hard | `Tree`, `Depth-First Search`, `Graph`, `Dynamic Programming`
833 | [Find And Replace in String](https://leetcode.com/problems/find-and-replace-in-string) | Medium | `Array`, `String`, `Sorting`
832 | [Flipping an Image](https://leetcode.com/problems/flipping-an-image) | Easy | `Array`, `Two Pointers`, `Matrix`, `Simulation`
831 | [Masking Personal Information](https://leetcode.com/problems/masking-personal-information) | Medium | `String`
830 | [Positions of Large Groups](https://leetcode.com/problems/positions-of-large-groups) | Easy | `String`
829 | [Consecutive Numbers Sum](https://leetcode.com/problems/consecutive-numbers-sum) | Hard | `Math`, `Enumeration`
828 | [Count Unique Characters of All Substrings of a Given String](https://leetcode.com/problems/count-unique-characters-of-all-substrings-of-a-given-string) | Hard | `String`, `Dynamic Programming`
827 | [Making A Large Island](https://leetcode.com/problems/making-a-large-island) | Hard | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
826 | [Most Profit Assigning Work](https://leetcode.com/problems/most-profit-assigning-work) | Medium | `Greedy`, `Array`, `Two Pointers`, `Binary Search`, `Sorting`
825 | [Friends Of Appropriate Ages](https://leetcode.com/problems/friends-of-appropriate-ages) | Medium | `Array`, `Two Pointers`, `Binary Search`, `Sorting`
824 | [Goat Latin](https://leetcode.com/problems/goat-latin) | Easy | `String`
823 | [Binary Trees With Factors](https://leetcode.com/problems/binary-trees-with-factors) | Medium | `Array`, `Hash Table`, `Dynamic Programming`
822 | [Card Flipping Game](https://leetcode.com/problems/card-flipping-game) | Medium | `Array`, `Hash Table`
821 | [Shortest Distance to a Character](https://leetcode.com/problems/shortest-distance-to-a-character) | Easy | `Array`, `Two Pointers`, `String`
820 | [Short Encoding of Words](https://leetcode.com/problems/short-encoding-of-words) | Medium | `Trie`, `Array`, `Hash Table`, `String`
819 | [Most Common Word](https://leetcode.com/problems/most-common-word) | Easy | `Hash Table`, `String`
818 | [Race Car](https://leetcode.com/problems/race-car) | Hard | `Dynamic Programming`
817 | [Linked List Components](https://leetcode.com/problems/linked-list-components) | Medium | `Hash Table`, `Linked List`
816 | [Ambiguous Coordinates](https://leetcode.com/problems/ambiguous-coordinates) | Medium | `String`, `Backtracking`
815 | [Bus Routes](https://leetcode.com/problems/bus-routes) | Hard | `Breadth-First Search`, `Array`, `Hash Table`
814 | [Binary Tree Pruning](https://leetcode.com/problems/binary-tree-pruning) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
813 | [Largest Sum of Averages](https://leetcode.com/problems/largest-sum-of-averages) | Medium | `Array`, `Dynamic Programming`
812 | [Largest Triangle Area](https://leetcode.com/problems/largest-triangle-area) | Easy | `Geometry`, `Array`, `Math`
811 | [Subdomain Visit Count](https://leetcode.com/problems/subdomain-visit-count) | Medium | `Array`, `Hash Table`, `String`
810 | [Chalkboard XOR Game](https://leetcode.com/problems/chalkboard-xor-game) | Hard | `Bit Manipulation`, `Brainteaser`, `Array`, `Math`, `Game Theory`
809 | [Expressive Words](https://leetcode.com/problems/expressive-words) | Medium | `Array`, `Two Pointers`, `String`
808 | [Soup Servings](https://leetcode.com/problems/soup-servings) | Medium | `Math`, `Dynamic Programming`, `Probability and Statistics`
807 | [Max Increase to Keep City Skyline](https://leetcode.com/problems/max-increase-to-keep-city-skyline) | Medium | `Greedy`, `Array`, `Matrix`
806 | [Number of Lines To Write String](https://leetcode.com/problems/number-of-lines-to-write-string) | Easy | `Array`, `String`
805 | [Split Array With Same Average](https://leetcode.com/problems/split-array-with-same-average) | Hard | `Bit Manipulation`, `Array`, `Math`, `Dynamic Programming`, `Bitmask`
804 | [Unique Morse Code Words](https://leetcode.com/problems/unique-morse-code-words) | Easy | `Array`, `Hash Table`, `String`
803 | [Bricks Falling When Hit](https://leetcode.com/problems/bricks-falling-when-hit) | Hard | `Union Find`, `Array`, `Matrix`
802 | [Find Eventual Safe States](https://leetcode.com/problems/find-eventual-safe-states) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Topological Sort`
801 | [Minimum Swaps To Make Sequences Increasing](https://leetcode.com/problems/minimum-swaps-to-make-sequences-increasing) | Hard | `Array`, `Dynamic Programming`
800 | [Similar RGB Color](https://leetcode.com/problems/similar-rgb-color) | Easy | `Math`, `String`, `Enumeration`
799 | [Champagne Tower](https://leetcode.com/problems/champagne-tower) | Medium | `Dynamic Programming`
798 | [Smallest Rotation with Highest Score](https://leetcode.com/problems/smallest-rotation-with-highest-score) | Hard | `Array`, `Prefix Sum`
797 | [All Paths From Source to Target](https://leetcode.com/problems/all-paths-from-source-to-target) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Backtracking`
796 | [Rotate String](https://leetcode.com/problems/rotate-string) | Easy | `String`, `String Matching`
795 | [Number of Subarrays with Bounded Maximum](https://leetcode.com/problems/number-of-subarrays-with-bounded-maximum) | Medium | `Array`, `Two Pointers`
794 | [Valid Tic-Tac-Toe State](https://leetcode.com/problems/valid-tic-tac-toe-state) | Medium | `Array`, `String`
793 | [Preimage Size of Factorial Zeroes Function](https://leetcode.com/problems/preimage-size-of-factorial-zeroes-function) | Hard | `Math`, `Binary Search`
792 | [Number of Matching Subsequences](https://leetcode.com/problems/number-of-matching-subsequences) | Medium | `Trie`, `Hash Table`, `String`, `Sorting`
791 | [Custom Sort String](https://leetcode.com/problems/custom-sort-string) | Medium | `Hash Table`, `String`, `Sorting`
790 | [Domino and Tromino Tiling](https://leetcode.com/problems/domino-and-tromino-tiling) | Medium | `Dynamic Programming`
789 | [Escape The Ghosts](https://leetcode.com/problems/escape-the-ghosts) | Medium | `Array`, `Math`
788 | [Rotated Digits](https://leetcode.com/problems/rotated-digits) | Medium | `Math`, `Dynamic Programming`
787 | [Cheapest Flights Within K Stops](https://leetcode.com/problems/cheapest-flights-within-k-stops) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Dynamic Programming`, `Shortest Path`, `Heap (Priority Queue)`
786 | [K-th Smallest Prime Fraction](https://leetcode.com/problems/k-th-smallest-prime-fraction) | Hard | `Array`, `Binary Search`, `Heap (Priority Queue)`
785 | [Is Graph Bipartite?](https://leetcode.com/problems/is-graph-bipartite) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
784 | [Letter Case Permutation](https://leetcode.com/problems/letter-case-permutation) | Medium | `Bit Manipulation`, `String`, `Backtracking`
783 | [Minimum Distance Between BST Nodes](https://leetcode.com/problems/minimum-distance-between-bst-nodes) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Search Tree`, `Binary Tree`
782 | [Transform to Chessboard](https://leetcode.com/problems/transform-to-chessboard) | Hard | `Bit Manipulation`, `Array`, `Math`, `Matrix`
781 | [Rabbits in Forest](https://leetcode.com/problems/rabbits-in-forest) | Medium | `Greedy`, `Hash Table`, `Math`
779 | [K-th Symbol in Grammar](https://leetcode.com/problems/k-th-symbol-in-grammar) | Medium | `Bit Manipulation`, `Recursion`, `Math`
778 | [Swim in Rising Water](https://leetcode.com/problems/swim-in-rising-water) | Hard | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Binary Search`, `Matrix`, `Heap (Priority Queue)`
777 | [Swap Adjacent in LR String](https://leetcode.com/problems/swap-adjacent-in-lr-string) | Medium | `Two Pointers`, `String`
776 | [Split BST](https://leetcode.com/problems/split-bst) | Medium | `Tree`, `Binary Search Tree`, `Recursion`, `Binary Tree`
775 | [Global and Local Inversions](https://leetcode.com/problems/global-and-local-inversions) | Medium | `Array`, `Math`
774 | [Minimize Max Distance to Gas Station](https://leetcode.com/problems/minimize-max-distance-to-gas-station) | Hard | `Array`, `Binary Search`
773 | [Sliding Puzzle](https://leetcode.com/problems/sliding-puzzle) | Hard | `Breadth-First Search`, `Array`, `Matrix`
772 | [Basic Calculator III](https://leetcode.com/problems/basic-calculator-iii) | Hard | `Stack`, `Recursion`, `Math`, `String`
771 | [Jewels and Stones](https://leetcode.com/problems/jewels-and-stones) | Easy | `Hash Table`, `String`
770 | [Basic Calculator IV](https://leetcode.com/problems/basic-calculator-iv) | Hard | `Stack`, `Recursion`, `Hash Table`, `Math`, `String`
769 | [Max Chunks To Make Sorted](https://leetcode.com/problems/max-chunks-to-make-sorted) | Medium | `Stack`, `Greedy`, `Array`, `Sorting`, `Monotonic Stack`
768 | [Max Chunks To Make Sorted II](https://leetcode.com/problems/max-chunks-to-make-sorted-ii) | Hard | `Stack`, `Greedy`, `Array`, `Sorting`, `Monotonic Stack`
767 | [Reorganize String](https://leetcode.com/problems/reorganize-string) | Medium | `Greedy`, `Hash Table`, `String`, `Counting`, `Sorting`, `Heap (Priority Queue)`
765 | [Couples Holding Hands](https://leetcode.com/problems/couples-holding-hands) | Hard | `Greedy`, `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
764 | [Largest Plus Sign](https://leetcode.com/problems/largest-plus-sign) | Medium | `Array`, `Dynamic Programming`
763 | [Partition Labels](https://leetcode.com/problems/partition-labels) | Medium | `Greedy`, `Hash Table`, `Two Pointers`, `String`
762 | [Prime Number of Set Bits in Binary Representation](https://leetcode.com/problems/prime-number-of-set-bits-in-binary-representation) | Easy | `Bit Manipulation`, `Math`
761 | [Special Binary String](https://leetcode.com/problems/special-binary-string) | Hard | `Recursion`, `String`
760 | [Find Anagram Mappings](https://leetcode.com/problems/find-anagram-mappings) | Easy | `Array`, `Hash Table`
759 | [Employee Free Time](https://leetcode.com/problems/employee-free-time) | Hard | `Array`, `Sorting`, `Heap (Priority Queue)`
758 | [Bold Words in String](https://leetcode.com/problems/bold-words-in-string) | Medium | `Trie`, `Array`, `Hash Table`, `String`, `String Matching`
757 | [Set Intersection Size At Least Two](https://leetcode.com/problems/set-intersection-size-at-least-two) | Hard | `Greedy`, `Array`, `Sorting`
756 | [Pyramid Transition Matrix](https://leetcode.com/problems/pyramid-transition-matrix) | Medium | `Bit Manipulation`, `Depth-First Search`, `Breadth-First Search`
755 | [Pour Water](https://leetcode.com/problems/pour-water) | Medium | `Array`, `Simulation`
754 | [Reach a Number](https://leetcode.com/problems/reach-a-number) | Medium | `Math`, `Binary Search`
753 | [Cracking the Safe](https://leetcode.com/problems/cracking-the-safe) | Hard | `Depth-First Search`, `Graph`, `Eulerian Circuit`
752 | [Open the Lock](https://leetcode.com/problems/open-the-lock) | Medium | `Breadth-First Search`, `Array`, `Hash Table`, `String`
751 | [IP to CIDR](https://leetcode.com/problems/ip-to-cidr) | Medium | `Bit Manipulation`, `String`
750 | [Number Of Corner Rectangles](https://leetcode.com/problems/number-of-corner-rectangles) | Medium | `Array`, `Math`, `Dynamic Programming`, `Matrix`
749 | [Contain Virus](https://leetcode.com/problems/contain-virus) | Hard | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`, `Simulation`
748 | [Shortest Completing Word](https://leetcode.com/problems/shortest-completing-word) | Easy | `Hash Table`, `String`
747 | [Largest Number At Least Twice of Others](https://leetcode.com/problems/largest-number-at-least-twice-of-others) | Easy | `Array`, `Sorting`
746 | [Min Cost Climbing Stairs](https://leetcode.com/problems/min-cost-climbing-stairs) | Easy | `Array`, `Dynamic Programming`
745 | [Prefix and Suffix Search](https://leetcode.com/problems/prefix-and-suffix-search) | Hard | `Design`, `Trie`, `String`
744 | [Find Smallest Letter Greater Than Target](https://leetcode.com/problems/find-smallest-letter-greater-than-target) | Easy | `Array`, `Binary Search`
743 | [Network Delay Time](https://leetcode.com/problems/network-delay-time) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Shortest Path`, `Heap (Priority Queue)`
742 | [Closest Leaf in a Binary Tree](https://leetcode.com/problems/closest-leaf-in-a-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
741 | [Cherry Pickup](https://leetcode.com/problems/cherry-pickup) | Hard | `Array`, `Dynamic Programming`, `Matrix`
740 | [Delete and Earn](https://leetcode.com/problems/delete-and-earn) | Medium | `Array`, `Hash Table`, `Dynamic Programming`
739 | [Daily Temperatures](https://leetcode.com/problems/daily-temperatures) | Medium | `Stack`, `Array`, `Monotonic Stack`
738 | [Monotone Increasing Digits](https://leetcode.com/problems/monotone-increasing-digits) | Medium | `Greedy`, `Math`
737 | [Sentence Similarity II](https://leetcode.com/problems/sentence-similarity-ii) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Hash Table`, `String`
736 | [Parse Lisp Expression](https://leetcode.com/problems/parse-lisp-expression) | Hard | `Stack`, `Recursion`, `Hash Table`, `String`
735 | [Asteroid Collision](https://leetcode.com/problems/asteroid-collision) | Medium | `Stack`, `Array`
734 | [Sentence Similarity](https://leetcode.com/problems/sentence-similarity) | Easy | `Array`, `Hash Table`, `String`
733 | [Flood Fill](https://leetcode.com/problems/flood-fill) | Easy | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`
732 | [My Calendar III](https://leetcode.com/problems/my-calendar-iii) | Hard | `Design`, `Segment Tree`, `Ordered Set`
731 | [My Calendar II](https://leetcode.com/problems/my-calendar-ii) | Medium | `Design`, `Segment Tree`, `Ordered Set`
730 | [Count Different Palindromic Subsequences](https://leetcode.com/problems/count-different-palindromic-subsequences) | Hard | `String`, `Dynamic Programming`
729 | [My Calendar I](https://leetcode.com/problems/my-calendar-i) | Medium | `Design`, `Segment Tree`, `Ordered Set`
728 | [Self Dividing Numbers](https://leetcode.com/problems/self-dividing-numbers) | Easy | `Math`
727 | [Minimum Window Subsequence](https://leetcode.com/problems/minimum-window-subsequence) | Hard | `String`, `Dynamic Programming`, `Sliding Window`
726 | [Number of Atoms](https://leetcode.com/problems/number-of-atoms) | Hard | `Stack`, `Hash Table`, `String`
725 | [Split Linked List in Parts](https://leetcode.com/problems/split-linked-list-in-parts) | Medium | `Linked List`
724 | [Find Pivot Index](https://leetcode.com/problems/find-pivot-index) | Easy | `Array`, `Prefix Sum`
723 | [Candy Crush](https://leetcode.com/problems/candy-crush) | Medium | `Array`, `Two Pointers`, `Matrix`, `Simulation`
722 | [Remove Comments](https://leetcode.com/problems/remove-comments) | Medium | `Array`, `String`
721 | [Accounts Merge](https://leetcode.com/problems/accounts-merge) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `String`
720 | [Longest Word in Dictionary](https://leetcode.com/problems/longest-word-in-dictionary) | Easy | `Trie`, `Array`, `Hash Table`, `String`, `Sorting`
719 | [Find K-th Smallest Pair Distance](https://leetcode.com/problems/find-k-th-smallest-pair-distance) | Hard | `Array`, `Two Pointers`, `Binary Search`, `Sorting`
718 | [Maximum Length of Repeated Subarray](https://leetcode.com/problems/maximum-length-of-repeated-subarray) | Medium | `Array`, `Binary Search`, `Dynamic Programming`, `Sliding Window`, `Hash Function`, `Rolling Hash`
717 | [1-bit and 2-bit Characters](https://leetcode.com/problems/1-bit-and-2-bit-characters) | Easy | `Array`
716 | [Max Stack](https://leetcode.com/problems/max-stack) | Easy | `Stack`, `Design`, `Linked List`, `Doubly-Linked List`, `Ordered Set`
715 | [Range Module](https://leetcode.com/problems/range-module) | Hard | `Design`, `Segment Tree`, `Ordered Set`
714 | [Best Time to Buy and Sell Stock with Transaction Fee](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-with-transaction-fee) | Medium | `Greedy`, `Array`, `Dynamic Programming`
713 | [Subarray Product Less Than K](https://leetcode.com/problems/subarray-product-less-than-k) | Medium | `Array`, `Sliding Window`
712 | [Minimum ASCII Delete Sum for Two Strings](https://leetcode.com/problems/minimum-ascii-delete-sum-for-two-strings) | Medium | `String`, `Dynamic Programming`
711 | [Number of Distinct Islands II](https://leetcode.com/problems/number-of-distinct-islands-ii) | Hard | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Hash Table`, `Hash Function`
710 | [Random Pick with Blacklist](https://leetcode.com/problems/random-pick-with-blacklist) | Hard | `Hash Table`, `Math`, `Binary Search`, `Sorting`, `Randomized`
709 | [To Lower Case](https://leetcode.com/problems/to-lower-case) | Easy | `String`
708 | [Insert into a Sorted Circular Linked List](https://leetcode.com/problems/insert-into-a-sorted-circular-linked-list) | Medium | `Linked List`
707 | [Design Linked List](https://leetcode.com/problems/design-linked-list) | Medium | `Design`, `Linked List`
706 | [Design HashMap](https://leetcode.com/problems/design-hashmap) | Easy | `Design`, `Array`, `Hash Table`, `Linked List`, `Hash Function`
705 | [Design HashSet](https://leetcode.com/problems/design-hashset) | Easy | `Design`, `Array`, `Hash Table`, `Linked List`, `Hash Function`
702 | [Search in a Sorted Array of Unknown Size](https://leetcode.com/problems/search-in-a-sorted-array-of-unknown-size) | Medium | `Array`, `Binary Search`, `Interactive`
701 | [Insert into a Binary Search Tree](https://leetcode.com/problems/insert-into-a-binary-search-tree) | Medium | `Tree`, `Binary Search Tree`, `Binary Tree`
700 | [Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree) | Easy | `Tree`, `Binary Search Tree`, `Binary Tree`
699 | [Falling Squares](https://leetcode.com/problems/falling-squares) | Hard | `Segment Tree`, `Array`, `Ordered Set`
698 | [Partition to K Equal Sum Subsets](https://leetcode.com/problems/partition-to-k-equal-sum-subsets) | Medium | `Bit Manipulation`, `Memoization`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
697 | [Degree of an Array](https://leetcode.com/problems/degree-of-an-array) | Easy | `Array`, `Hash Table`
696 | [Count Binary Substrings](https://leetcode.com/problems/count-binary-substrings) | Easy | `Two Pointers`, `String`
694 | [Number of Distinct Islands](https://leetcode.com/problems/number-of-distinct-islands) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Hash Table`, `Hash Function`
693 | [Binary Number with Alternating Bits](https://leetcode.com/problems/binary-number-with-alternating-bits) | Easy | `Bit Manipulation`
692 | [Top K Frequent Words](https://leetcode.com/problems/top-k-frequent-words) | Medium | `Trie`, `Hash Table`, `String`, `Bucket Sort`, `Counting`, `Sorting`, `Heap (Priority Queue)`
691 | [Stickers to Spell Word](https://leetcode.com/problems/stickers-to-spell-word) | Hard | `Bit Manipulation`, `Dynamic Programming`, `Backtracking`, `Bitmask`
690 | [Employee Importance](https://leetcode.com/problems/employee-importance) | Easy | `Depth-First Search`, `Breadth-First Search`, `Hash Table`
689 | [Maximum Sum of 3 Non-Overlapping Subarrays](https://leetcode.com/problems/maximum-sum-of-3-non-overlapping-subarrays) | Hard | `Array`, `Dynamic Programming`
688 | [Knight Probability in Chessboard](https://leetcode.com/problems/knight-probability-in-chessboard) | Medium | `Dynamic Programming`
687 | [Longest Univalue Path](https://leetcode.com/problems/longest-univalue-path) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
686 | [Repeated String Match](https://leetcode.com/problems/repeated-string-match) | Medium | `String`, `String Matching`
685 | [Redundant Connection II](https://leetcode.com/problems/redundant-connection-ii) | Hard | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
684 | [Redundant Connection](https://leetcode.com/problems/redundant-connection) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
683 | [K Empty Slots](https://leetcode.com/problems/k-empty-slots) | Hard | `Binary Indexed Tree`, `Array`, `Ordered Set`, `Sliding Window`
682 | [Baseball Game](https://leetcode.com/problems/baseball-game) | Easy | `Stack`, `Array`, `Simulation`
681 | [Next Closest Time](https://leetcode.com/problems/next-closest-time) | Medium | `String`, `Enumeration`
680 | [Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii) | Easy | `Greedy`, `Two Pointers`, `String`
679 | [24 Game](https://leetcode.com/problems/24-game) | Hard | `Array`, `Math`, `Backtracking`
678 | [Valid Parenthesis String](https://leetcode.com/problems/valid-parenthesis-string) | Medium | `Stack`, `Greedy`, `String`, `Dynamic Programming`
677 | [Map Sum Pairs](https://leetcode.com/problems/map-sum-pairs) | Medium | `Design`, `Trie`, `Hash Table`, `String`
676 | [Implement Magic Dictionary](https://leetcode.com/problems/implement-magic-dictionary) | Medium | `Design`, `Trie`, `Hash Table`, `String`
675 | [Cut Off Trees for Golf Event](https://leetcode.com/problems/cut-off-trees-for-golf-event) | Hard | `Breadth-First Search`, `Array`, `Matrix`, `Heap (Priority Queue)`
673 | [Number of Longest Increasing Subsequence](https://leetcode.com/problems/number-of-longest-increasing-subsequence) | Medium | `Binary Indexed Tree`, `Segment Tree`, `Array`, `Dynamic Programming`
672 | [Bulb Switcher II](https://leetcode.com/problems/bulb-switcher-ii) | Medium | `Bit Manipulation`, `Depth-First Search`, `Breadth-First Search`, `Math`
671 | [Second Minimum Node In a Binary Tree](https://leetcode.com/problems/second-minimum-node-in-a-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Binary Tree`
669 | [Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
668 | [Kth Smallest Number in Multiplication Table](https://leetcode.com/problems/kth-smallest-number-in-multiplication-table) | Hard | `Binary Search`
667 | [Beautiful Arrangement II](https://leetcode.com/problems/beautiful-arrangement-ii) | Medium | `Array`, `Math`
666 | [Path Sum IV](https://leetcode.com/problems/path-sum-iv) | Medium | `Tree`, `Depth-First Search`, `Array`, `Binary Tree`
665 | [Non-decreasing Array](https://leetcode.com/problems/non-decreasing-array) | Medium | `Array`
664 | [Strange Printer](https://leetcode.com/problems/strange-printer) | Hard | `String`, `Dynamic Programming`
663 | [Equal Tree Partition](https://leetcode.com/problems/equal-tree-partition) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
662 | [Maximum Width of Binary Tree](https://leetcode.com/problems/maximum-width-of-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
661 | [Image Smoother](https://leetcode.com/problems/image-smoother) | Easy | `Array`, `Matrix`
660 | [Remove 9](https://leetcode.com/problems/remove-9) | Hard | `Math`
659 | [Split Array into Consecutive Subsequences](https://leetcode.com/problems/split-array-into-consecutive-subsequences) | Medium | `Greedy`, `Array`, `Hash Table`, `Heap (Priority Queue)`
658 | [Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements) | Medium | `Array`, `Two Pointers`, `Binary Search`, `Sorting`, `Heap (Priority Queue)`
657 | [Robot Return to Origin](https://leetcode.com/problems/robot-return-to-origin) | Easy | `String`, `Simulation`
656 | [Coin Path](https://leetcode.com/problems/coin-path) | Hard | `Array`, `Dynamic Programming`
655 | [Print Binary Tree](https://leetcode.com/problems/print-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
654 | [Maximum Binary Tree](https://leetcode.com/problems/maximum-binary-tree) | Medium | `Stack`, `Tree`, `Array`, `Divide and Conquer`, `Binary Tree`, `Monotonic Stack`
653 | [Two Sum IV - Input is a BST](https://leetcode.com/problems/two-sum-iv-input-is-a-bst) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Search Tree`, `Hash Table`, `Two Pointers`, `Binary Tree`
652 | [Find Duplicate Subtrees](https://leetcode.com/problems/find-duplicate-subtrees) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
651 | [4 Keys Keyboard](https://leetcode.com/problems/4-keys-keyboard) | Medium | `Math`, `Dynamic Programming`
650 | [2 Keys Keyboard](https://leetcode.com/problems/2-keys-keyboard) | Medium | `Math`, `Dynamic Programming`
649 | [Dota2 Senate](https://leetcode.com/problems/dota2-senate) | Medium | `Greedy`, `Queue`, `String`
648 | [Replace Words](https://leetcode.com/problems/replace-words) | Medium | `Trie`, `Array`, `Hash Table`, `String`
647 | [Palindromic Substrings](https://leetcode.com/problems/palindromic-substrings) | Medium | `String`, `Dynamic Programming`
646 | [Maximum Length of Pair Chain](https://leetcode.com/problems/maximum-length-of-pair-chain) | Medium | `Greedy`, `Array`, `Dynamic Programming`, `Sorting`
645 | [Set Mismatch](https://leetcode.com/problems/set-mismatch) | Easy | `Bit Manipulation`, `Array`, `Hash Table`, `Sorting`
644 | [Maximum Average Subarray II](https://leetcode.com/problems/maximum-average-subarray-ii) | Hard | `Array`, `Binary Search`
643 | [Maximum Average Subarray I](https://leetcode.com/problems/maximum-average-subarray-i) | Easy | `Array`, `Sliding Window`
642 | [Design Search Autocomplete System](https://leetcode.com/problems/design-search-autocomplete-system) | Hard | `Design`, `Trie`, `String`, `Data Stream`
641 | [Design Circular Deque](https://leetcode.com/problems/design-circular-deque) | Medium | `Design`, `Queue`, `Array`, `Linked List`
640 | [Solve the Equation](https://leetcode.com/problems/solve-the-equation) | Medium | `Math`, `String`, `Simulation`
639 | [Decode Ways II](https://leetcode.com/problems/decode-ways-ii) | Hard | `String`, `Dynamic Programming`
638 | [Shopping Offers](https://leetcode.com/problems/shopping-offers) | Medium | `Bit Manipulation`, `Memoization`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
637 | [Average of Levels in Binary Tree](https://leetcode.com/problems/average-of-levels-in-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
636 | [Exclusive Time of Functions](https://leetcode.com/problems/exclusive-time-of-functions) | Medium | `Stack`, `Array`
635 | [Design Log Storage System](https://leetcode.com/problems/design-log-storage-system) | Medium | `Design`, `Hash Table`, `String`, `Ordered Set`
634 | [Find the Derangement of An Array](https://leetcode.com/problems/find-the-derangement-of-an-array) | Medium | `Math`, `Dynamic Programming`
633 | [Sum of Square Numbers](https://leetcode.com/problems/sum-of-square-numbers) | Medium | `Math`, `Two Pointers`, `Binary Search`
632 | [Smallest Range Covering Elements from K Lists](https://leetcode.com/problems/smallest-range-covering-elements-from-k-lists) | Hard | `Greedy`, `Array`, `Hash Table`, `Sorting`, `Sliding Window`, `Heap (Priority Queue)`
631 | [Design Excel Sum Formula](https://leetcode.com/problems/design-excel-sum-formula) | Hard | `Graph`, `Design`, `Topological Sort`
630 | [Course Schedule III](https://leetcode.com/problems/course-schedule-iii) | Hard | `Greedy`, `Array`, `Heap (Priority Queue)`
629 | [K Inverse Pairs Array](https://leetcode.com/problems/k-inverse-pairs-array) | Hard | `Dynamic Programming`
628 | [Maximum Product of Three Numbers](https://leetcode.com/problems/maximum-product-of-three-numbers) | Easy | `Array`, `Math`, `Sorting`
627 | [Swap Salary](https://leetcode.com/problems/swap-salary) | Easy | `Database`
626 | [Exchange Seats](https://leetcode.com/problems/exchange-seats) | Medium | `Database`
625 | [Minimum Factorization](https://leetcode.com/problems/minimum-factorization) | Medium | `Greedy`, `Math`
624 | [Maximum Distance in Arrays](https://leetcode.com/problems/maximum-distance-in-arrays) | Medium | `Greedy`, `Array`
623 | [Add One Row to Tree](https://leetcode.com/problems/add-one-row-to-tree) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
622 | [Design Circular Queue](https://leetcode.com/problems/design-circular-queue) | Medium | `Design`, `Queue`, `Array`, `Linked List`
621 | [Task Scheduler](https://leetcode.com/problems/task-scheduler) | Medium | `Greedy`, `Array`, `Hash Table`, `Counting`, `Sorting`, `Heap (Priority Queue)`
620 | [Not Boring Movies](https://leetcode.com/problems/not-boring-movies) | Easy | `Database`
619 | [Biggest Single Number](https://leetcode.com/problems/biggest-single-number) | Easy | `Database`
618 | [Students Report By Geography](https://leetcode.com/problems/students-report-by-geography) | Hard | `Database`
617 | [Merge Two Binary Trees](https://leetcode.com/problems/merge-two-binary-trees) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
616 | [Add Bold Tag in String](https://leetcode.com/problems/add-bold-tag-in-string) | Medium | `Trie`, `Array`, `Hash Table`, `String`, `String Matching`
615 | [Average Salary: Departments VS Company](https://leetcode.com/problems/average-salary-departments-vs-company) | Hard | `Database`
614 | [Second Degree Follower](https://leetcode.com/problems/second-degree-follower) | Medium | `Database`
613 | [Shortest Distance in a Line](https://leetcode.com/problems/shortest-distance-in-a-line) | Easy | `Database`
612 | [Shortest Distance in a Plane](https://leetcode.com/problems/shortest-distance-in-a-plane) | Medium | `Database`
611 | [Valid Triangle Number](https://leetcode.com/problems/valid-triangle-number) | Medium | `Greedy`, `Array`, `Two Pointers`, `Binary Search`, `Sorting`
610 | [Triangle Judgement](https://leetcode.com/problems/triangle-judgement) | Easy | `Database`
609 | [Find Duplicate File in System](https://leetcode.com/problems/find-duplicate-file-in-system) | Medium | `Array`, `Hash Table`, `String`
608 | [Tree Node](https://leetcode.com/problems/tree-node) | Medium | `Database`
607 | [Sales Person](https://leetcode.com/problems/sales-person) | Easy | `Database`
606 | [Construct String from Binary Tree](https://leetcode.com/problems/construct-string-from-binary-tree) | Easy | `Tree`, `Depth-First Search`, `String`, `Binary Tree`
605 | [Can Place Flowers](https://leetcode.com/problems/can-place-flowers) | Easy | `Greedy`, `Array`
604 | [Design Compressed String Iterator](https://leetcode.com/problems/design-compressed-string-iterator) | Easy | `Design`, `Array`, `Hash Table`, `String`, `Iterator`
603 | [Consecutive Available Seats](https://leetcode.com/problems/consecutive-available-seats) | Easy | `Database`
602 | [Friend Requests II: Who Has the Most Friends](https://leetcode.com/problems/friend-requests-ii-who-has-the-most-friends) | Medium | `Database`
601 | [Human Traffic of Stadium](https://leetcode.com/problems/human-traffic-of-stadium) | Hard | `Database`
600 | [Non-negative Integers without Consecutive Ones](https://leetcode.com/problems/non-negative-integers-without-consecutive-ones) | Hard | `Dynamic Programming`
599 | [Minimum Index Sum of Two Lists](https://leetcode.com/problems/minimum-index-sum-of-two-lists) | Easy | `Array`, `Hash Table`, `String`
598 | [Range Addition II](https://leetcode.com/problems/range-addition-ii) | Easy | `Array`, `Math`
597 | [Friend Requests I: Overall Acceptance Rate](https://leetcode.com/problems/friend-requests-i-overall-acceptance-rate) | Easy | `Database`
596 | [Classes More Than 5 Students](https://leetcode.com/problems/classes-more-than-5-students) | Easy | `Database`
595 | [Big Countries](https://leetcode.com/problems/big-countries) | Easy | `Database`
594 | [Longest Harmonious Subsequence](https://leetcode.com/problems/longest-harmonious-subsequence) | Easy | `Array`, `Hash Table`, `Sorting`
593 | [Valid Square](https://leetcode.com/problems/valid-square) | Medium | `Geometry`, `Math`
592 | [Fraction Addition and Subtraction](https://leetcode.com/problems/fraction-addition-and-subtraction) | Medium | `Math`, `String`, `Simulation`
591 | [Tag Validator](https://leetcode.com/problems/tag-validator) | Hard | `Stack`, `String`
590 | [N-ary Tree Postorder Traversal](https://leetcode.com/problems/n-ary-tree-postorder-traversal) | Easy | `Stack`, `Tree`, `Depth-First Search`
589 | [N-ary Tree Preorder Traversal](https://leetcode.com/problems/n-ary-tree-preorder-traversal) | Easy | `Stack`, `Tree`, `Depth-First Search`
588 | [Design In-Memory File System](https://leetcode.com/problems/design-in-memory-file-system) | Hard | `Design`, `Trie`, `Hash Table`, `String`
587 | [Erect the Fence](https://leetcode.com/problems/erect-the-fence) | Hard | `Geometry`, `Array`, `Math`
586 | [Customer Placing the Largest Number of Orders](https://leetcode.com/problems/customer-placing-the-largest-number-of-orders) | Easy | `Database`
585 | [Investments in 2016](https://leetcode.com/problems/investments-in-2016) | Medium | `Database`
584 | [Find Customer Referee](https://leetcode.com/problems/find-customer-referee) | Easy | `Database`
583 | [Delete Operation for Two Strings](https://leetcode.com/problems/delete-operation-for-two-strings) | Medium | `String`, `Dynamic Programming`
582 | [Kill Process](https://leetcode.com/problems/kill-process) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Array`, `Hash Table`
581 | [Shortest Unsorted Continuous Subarray](https://leetcode.com/problems/shortest-unsorted-continuous-subarray) | Medium | `Stack`, `Greedy`, `Array`, `Two Pointers`, `Sorting`, `Monotonic Stack`
580 | [Count Student Number in Departments](https://leetcode.com/problems/count-student-number-in-departments) | Medium | `Database`
579 | [Find Cumulative Salary of an Employee](https://leetcode.com/problems/find-cumulative-salary-of-an-employee) | Hard | `Database`
578 | [Get Highest Answer Rate Question](https://leetcode.com/problems/get-highest-answer-rate-question) | Medium | `Database`
577 | [Employee Bonus](https://leetcode.com/problems/employee-bonus) | Easy | `Database`
576 | [Out of Boundary Paths](https://leetcode.com/problems/out-of-boundary-paths) | Medium | `Dynamic Programming`
575 | [Distribute Candies](https://leetcode.com/problems/distribute-candies) | Easy | `Array`, `Hash Table`
574 | [Winning Candidate](https://leetcode.com/problems/winning-candidate) | Medium | `Database`
573 | [Squirrel Simulation](https://leetcode.com/problems/squirrel-simulation) | Medium | `Array`, `Math`
572 | [Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree) | Easy | `Tree`, `Depth-First Search`, `Binary Tree`, `String Matching`, `Hash Function`
571 | [Find Median Given Frequency of Numbers](https://leetcode.com/problems/find-median-given-frequency-of-numbers) | Hard | `Database`
570 | [Managers with at Least 5 Direct Reports](https://leetcode.com/problems/managers-with-at-least-5-direct-reports) | Medium | `Database`
569 | [Median Employee Salary](https://leetcode.com/problems/median-employee-salary) | Hard | `Database`
568 | [Maximum Vacation Days](https://leetcode.com/problems/maximum-vacation-days) | Hard | `Array`, `Dynamic Programming`, `Matrix`
567 | [Permutation in String](https://leetcode.com/problems/permutation-in-string) | Medium | `Hash Table`, `Two Pointers`, `String`, `Sliding Window`
566 | [Reshape the Matrix](https://leetcode.com/problems/reshape-the-matrix) | Easy | `Array`, `Matrix`, `Simulation`
565 | [Array Nesting](https://leetcode.com/problems/array-nesting) | Medium | `Depth-First Search`, `Array`
564 | [Find the Closest Palindrome](https://leetcode.com/problems/find-the-closest-palindrome) | Hard | `Math`, `String`
563 | [Binary Tree Tilt](https://leetcode.com/problems/binary-tree-tilt) | Easy | `Tree`, `Depth-First Search`, `Binary Tree`
562 | [Longest Line of Consecutive One in Matrix](https://leetcode.com/problems/longest-line-of-consecutive-one-in-matrix) | Medium | `Array`, `Dynamic Programming`, `Matrix`
561 | [Array Partition I](https://leetcode.com/problems/array-partition-i) | Easy | `Greedy`, `Array`, `Counting Sort`, `Sorting`
560 | [Subarray Sum Equals K](https://leetcode.com/problems/subarray-sum-equals-k) | Medium | `Array`, `Hash Table`, `Prefix Sum`
559 | [Maximum Depth of N-ary Tree](https://leetcode.com/problems/maximum-depth-of-n-ary-tree) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`
558 | [Logical OR of Two Binary Grids Represented as Quad-Trees](https://leetcode.com/problems/logical-or-of-two-binary-grids-represented-as-quad-trees) | Medium | `Tree`, `Divide and Conquer`
556 | [Next Greater Element III](https://leetcode.com/problems/next-greater-element-iii) | Medium | `Math`, `Two Pointers`, `String`
555 | [Split Concatenated Strings](https://leetcode.com/problems/split-concatenated-strings) | Medium | `Greedy`, `Array`, `String`
554 | [Brick Wall](https://leetcode.com/problems/brick-wall) | Medium | `Array`, `Hash Table`
553 | [Optimal Division](https://leetcode.com/problems/optimal-division) | Medium | `Array`, `Math`, `Dynamic Programming`
552 | [Student Attendance Record II](https://leetcode.com/problems/student-attendance-record-ii) | Hard | `Dynamic Programming`
551 | [Student Attendance Record I](https://leetcode.com/problems/student-attendance-record-i) | Easy | `String`
550 | [Game Play Analysis IV](https://leetcode.com/problems/game-play-analysis-iv) | Medium | `Database`
549 | [Binary Tree Longest Consecutive Sequence II](https://leetcode.com/problems/binary-tree-longest-consecutive-sequence-ii) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
548 | [Split Array with Equal Sum](https://leetcode.com/problems/split-array-with-equal-sum) | Hard | `Array`, `Prefix Sum`
547 | [Number of Provinces](https://leetcode.com/problems/number-of-provinces) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
546 | [Remove Boxes](https://leetcode.com/problems/remove-boxes) | Hard | `Memoization`, `Array`, `Dynamic Programming`
545 | [Boundary of Binary Tree](https://leetcode.com/problems/boundary-of-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
544 | [Output Contest Matches](https://leetcode.com/problems/output-contest-matches) | Medium | `Recursion`, `String`, `Simulation`
543 | [Diameter of Binary Tree](https://leetcode.com/problems/diameter-of-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Binary Tree`
542 | [01 Matrix](https://leetcode.com/problems/01-matrix) | Medium | `Breadth-First Search`, `Array`, `Dynamic Programming`, `Matrix`
541 | [Reverse String II](https://leetcode.com/problems/reverse-string-ii) | Easy | `Two Pointers`, `String`
540 | [Single Element in a Sorted Array](https://leetcode.com/problems/single-element-in-a-sorted-array) | Medium | `Array`, `Binary Search`
538 | [Convert BST to Greater Tree](https://leetcode.com/problems/convert-bst-to-greater-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
536 | [Construct Binary Tree from String](https://leetcode.com/problems/construct-binary-tree-from-string) | Medium | `Tree`, `Depth-First Search`, `String`, `Binary Tree`
535 | [Encode and Decode TinyURL](https://leetcode.com/problems/encode-and-decode-tinyurl) | Medium | `Design`, `Hash Table`, `String`, `Hash Function`
534 | [Game Play Analysis III](https://leetcode.com/problems/game-play-analysis-iii) | Medium | `Database`
533 | [Lonely Pixel II](https://leetcode.com/problems/lonely-pixel-ii) | Medium | `Array`, `Hash Table`, `Matrix`
532 | [K-diff Pairs in an Array](https://leetcode.com/problems/k-diff-pairs-in-an-array) | Medium | `Array`, `Hash Table`, `Two Pointers`, `Binary Search`, `Sorting`
531 | [Lonely Pixel I](https://leetcode.com/problems/lonely-pixel-i) | Medium | `Array`, `Hash Table`, `Matrix`
530 | [Minimum Absolute Difference in BST](https://leetcode.com/problems/minimum-absolute-difference-in-bst) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Search Tree`, `Binary Tree`
529 | [Minesweeper](https://leetcode.com/problems/minesweeper) | Medium | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`
528 | [Random Pick with Weight](https://leetcode.com/problems/random-pick-with-weight) | Medium | `Math`, `Binary Search`, `Prefix Sum`, `Randomized`
527 | [Word Abbreviation](https://leetcode.com/problems/word-abbreviation) | Hard | `Greedy`, `Trie`, `Array`, `String`, `Sorting`
526 | [Beautiful Arrangement](https://leetcode.com/problems/beautiful-arrangement) | Medium | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
525 | [Contiguous Array](https://leetcode.com/problems/contiguous-array) | Medium | `Array`, `Hash Table`, `Prefix Sum`
524 | [Longest Word in Dictionary through Deleting](https://leetcode.com/problems/longest-word-in-dictionary-through-deleting) | Medium | `Array`, `Two Pointers`, `String`, `Sorting`
523 | [Continuous Subarray Sum](https://leetcode.com/problems/continuous-subarray-sum) | Medium | `Array`, `Hash Table`, `Math`, `Prefix Sum`
522 | [Longest Uncommon Subsequence II](https://leetcode.com/problems/longest-uncommon-subsequence-ii) | Medium | `Array`, `Hash Table`, `Two Pointers`, `String`, `Sorting`
521 | [Longest Uncommon Subsequence I](https://leetcode.com/problems/longest-uncommon-subsequence-i) | Easy | `String`
519 | [Random Flip Matrix](https://leetcode.com/problems/random-flip-matrix) | Medium | `Reservoir Sampling`, `Hash Table`, `Math`, `Randomized`
517 | [Super Washing Machines](https://leetcode.com/problems/super-washing-machines) | Hard | `Greedy`, `Array`
516 | [Longest Palindromic Subsequence](https://leetcode.com/problems/longest-palindromic-subsequence) | Medium | `String`, `Dynamic Programming`
515 | [Find Largest Value in Each Tree Row](https://leetcode.com/problems/find-largest-value-in-each-tree-row) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
514 | [Freedom Trail](https://leetcode.com/problems/freedom-trail) | Hard | `Depth-First Search`, `Breadth-First Search`, `String`, `Dynamic Programming`
513 | [Find Bottom Left Tree Value](https://leetcode.com/problems/find-bottom-left-tree-value) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
512 | [Game Play Analysis II](https://leetcode.com/problems/game-play-analysis-ii) | Easy | `Database`
511 | [Game Play Analysis I](https://leetcode.com/problems/game-play-analysis-i) | Easy | `Database`
510 | [Inorder Successor in BST II](https://leetcode.com/problems/inorder-successor-in-bst-ii) | Medium | `Tree`, `Binary Search Tree`, `Binary Tree`
508 | [Most Frequent Subtree Sum](https://leetcode.com/problems/most-frequent-subtree-sum) | Medium | `Tree`, `Depth-First Search`, `Hash Table`, `Binary Tree`
505 | [The Maze II](https://leetcode.com/problems/the-maze-ii) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Shortest Path`, `Heap (Priority Queue)`
504 | [Base 7](https://leetcode.com/problems/base-7) | Easy | `Math`
503 | [Next Greater Element II](https://leetcode.com/problems/next-greater-element-ii) | Medium | `Stack`, `Array`, `Monotonic Stack`
502 | [IPO](https://leetcode.com/problems/ipo) | Hard | `Greedy`, `Array`, `Sorting`, `Heap (Priority Queue)`
501 | [Find Mode in Binary Search Tree](https://leetcode.com/problems/find-mode-in-binary-search-tree) | Easy | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
500 | [Keyboard Row](https://leetcode.com/problems/keyboard-row) | Easy | `Array`, `Hash Table`, `String`
499 | [The Maze III](https://leetcode.com/problems/the-maze-iii) | Hard | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Shortest Path`, `Heap (Priority Queue)`
498 | [Diagonal Traverse](https://leetcode.com/problems/diagonal-traverse) | Medium | `Array`, `Matrix`, `Simulation`
497 | [Random Point in Non-overlapping Rectangles](https://leetcode.com/problems/random-point-in-non-overlapping-rectangles) | Medium | `Reservoir Sampling`, `Math`, `Binary Search`, `Ordered Set`, `Prefix Sum`, `Randomized`
496 | [Next Greater Element I](https://leetcode.com/problems/next-greater-element-i) | Easy | `Stack`, `Array`, `Hash Table`, `Monotonic Stack`
495 | [Teemo Attacking](https://leetcode.com/problems/teemo-attacking) | Easy | `Array`, `Simulation`
494 | [Target Sum](https://leetcode.com/problems/target-sum) | Medium | `Array`, `Dynamic Programming`, `Backtracking`
493 | [Reverse Pairs](https://leetcode.com/problems/reverse-pairs) | Hard | `Binary Indexed Tree`, `Segment Tree`, `Array`, `Binary Search`, `Divide and Conquer`, `Ordered Set`, `Merge Sort`
492 | [Construct the Rectangle](https://leetcode.com/problems/construct-the-rectangle) | Easy | `Math`
491 | [Increasing Subsequences](https://leetcode.com/problems/increasing-subsequences) | Medium | `Bit Manipulation`, `Array`, `Hash Table`, `Backtracking`
490 | [The Maze](https://leetcode.com/problems/the-maze) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`
489 | [Robot Room Cleaner](https://leetcode.com/problems/robot-room-cleaner) | Hard | `Backtracking`, `Interactive`
487 | [Max Consecutive Ones II](https://leetcode.com/problems/max-consecutive-ones-ii) | Medium | `Array`, `Dynamic Programming`, `Sliding Window`
486 | [Predict the Winner](https://leetcode.com/problems/predict-the-winner) | Medium | `Recursion`, `Array`, `Math`, `Dynamic Programming`, `Game Theory`
485 | [Max Consecutive Ones](https://leetcode.com/problems/max-consecutive-ones) | Easy | `Array`
484 | [Find Permutation](https://leetcode.com/problems/find-permutation) | Medium | `Stack`, `Greedy`, `Array`
483 | [Smallest Good Base](https://leetcode.com/problems/smallest-good-base) | Hard | `Math`, `Binary Search`
482 | [License Key Formatting](https://leetcode.com/problems/license-key-formatting) | Easy | `String`
481 | [Magical String](https://leetcode.com/problems/magical-string) | Medium | `Two Pointers`, `String`
480 | [Sliding Window Median](https://leetcode.com/problems/sliding-window-median) | Hard | `Array`, `Hash Table`, `Sliding Window`, `Heap (Priority Queue)`
478 | [Generate Random Point in a Circle](https://leetcode.com/problems/generate-random-point-in-a-circle) | Medium | `Geometry`, `Math`, `Rejection Sampling`, `Randomized`
476 | [Number Complement](https://leetcode.com/problems/number-complement) | Easy | `Bit Manipulation`
475 | [Heaters](https://leetcode.com/problems/heaters) | Medium | `Array`, `Binary Search`, `Sorting`
474 | [Ones and Zeroes](https://leetcode.com/problems/ones-and-zeroes) | Medium | `Array`, `String`, `Dynamic Programming`
473 | [Matchsticks to Square](https://leetcode.com/problems/matchsticks-to-square) | Medium | `Bit Manipulation`, `Array`, `Dynamic Programming`, `Backtracking`, `Bitmask`
472 | [Concatenated Words](https://leetcode.com/problems/concatenated-words) | Hard | `Depth-First Search`, `Trie`, `String`, `Dynamic Programming`
471 | [Encode String with Shortest Length](https://leetcode.com/problems/encode-string-with-shortest-length) | Hard | `String`, `Dynamic Programming`
470 | [Implement Rand10() Using Rand7()](https://leetcode.com/problems/implement-rand10-using-rand7) | Medium | `Math`, `Rejection Sampling`, `Probability and Statistics`, `Randomized`
469 | [Convex Polygon](https://leetcode.com/problems/convex-polygon) | Medium | `Geometry`, `Math`
468 | [Validate IP Address](https://leetcode.com/problems/validate-ip-address) | Medium | `String`
467 | [Unique Substrings in Wraparound String](https://leetcode.com/problems/unique-substrings-in-wraparound-string) | Medium | `String`, `Dynamic Programming`
466 | [Count The Repetitions](https://leetcode.com/problems/count-the-repetitions) | Hard | `String`, `Dynamic Programming`
465 | [Optimal Account Balancing](https://leetcode.com/problems/optimal-account-balancing) | Hard | `Array`, `Backtracking`
464 | [Can I Win](https://leetcode.com/problems/can-i-win) | Medium | `Bit Manipulation`, `Memoization`, `Math`, `Dynamic Programming`, `Bitmask`, `Game Theory`
463 | [Island Perimeter](https://leetcode.com/problems/island-perimeter) | Easy | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`
462 | [Minimum Moves to Equal Array Elements II](https://leetcode.com/problems/minimum-moves-to-equal-array-elements-ii) | Medium | `Array`, `Math`, `Sorting`
460 | [LFU Cache](https://leetcode.com/problems/lfu-cache) | Hard | `Design`, `Hash Table`, `Linked List`, `Doubly-Linked List`
459 | [Repeated Substring Pattern](https://leetcode.com/problems/repeated-substring-pattern) | Easy | `String`, `String Matching`
458 | [Poor Pigs](https://leetcode.com/problems/poor-pigs) | Hard | `Math`, `Dynamic Programming`, `Combinatorics`
457 | [Circular Array Loop](https://leetcode.com/problems/circular-array-loop) | Medium | `Array`, `Hash Table`, `Two Pointers`
456 | [132 Pattern](https://leetcode.com/problems/132-pattern) | Medium | `Stack`, `Array`, `Binary Search`, `Ordered Set`, `Monotonic Stack`
455 | [Assign Cookies](https://leetcode.com/problems/assign-cookies) | Easy | `Greedy`, `Array`, `Sorting`
454 | [4Sum II](https://leetcode.com/problems/4sum-ii) | Medium | `Array`, `Hash Table`
453 | [Minimum Moves to Equal Array Elements](https://leetcode.com/problems/minimum-moves-to-equal-array-elements) | Easy | `Array`, `Math`
452 | [Minimum Number of Arrows to Burst Balloons](https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons) | Medium | `Greedy`, `Array`, `Sorting`
450 | [Delete Node in a BST](https://leetcode.com/problems/delete-node-in-a-bst) | Medium | `Tree`, `Binary Search Tree`, `Binary Tree`
449 | [Serialize and Deserialize BST](https://leetcode.com/problems/serialize-and-deserialize-bst) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Design`, `Binary Search Tree`, `String`, `Binary Tree`
447 | [Number of Boomerangs](https://leetcode.com/problems/number-of-boomerangs) | Medium | `Array`, `Hash Table`, `Math`
446 | [Arithmetic Slices II - Subsequence](https://leetcode.com/problems/arithmetic-slices-ii-subsequence) | Hard | `Array`, `Dynamic Programming`
445 | [Add Two Numbers II](https://leetcode.com/problems/add-two-numbers-ii) | Medium | `Stack`, `Linked List`, `Math`
444 | [Sequence Reconstruction](https://leetcode.com/problems/sequence-reconstruction) | Medium | `Graph`, `Topological Sort`, `Array`
440 | [K-th Smallest in Lexicographical Order](https://leetcode.com/problems/k-th-smallest-in-lexicographical-order) | Hard | `Trie`
439 | [Ternary Expression Parser](https://leetcode.com/problems/ternary-expression-parser) | Medium | `Stack`, `Recursion`, `String`
438 | [Find All Anagrams in a String](https://leetcode.com/problems/find-all-anagrams-in-a-string) | Medium | `Hash Table`, `String`, `Sliding Window`
437 | [Path Sum III](https://leetcode.com/problems/path-sum-iii) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
436 | [Find Right Interval](https://leetcode.com/problems/find-right-interval) | Medium | `Array`, `Binary Search`, `Sorting`
435 | [Non-overlapping Intervals](https://leetcode.com/problems/non-overlapping-intervals) | Medium | `Greedy`, `Array`, `Dynamic Programming`, `Sorting`
434 | [Number of Segments in a String](https://leetcode.com/problems/number-of-segments-in-a-string) | Easy | `String`
433 | [Minimum Genetic Mutation](https://leetcode.com/problems/minimum-genetic-mutation) | Medium | `Breadth-First Search`, `Hash Table`, `String`
432 | [All O`one Data Structure](https://leetcode.com/problems/all-oone-data-structure) | Hard | `Design`, `Hash Table`, `Linked List`, `Doubly-Linked List`
431 | [Encode N-ary Tree to Binary Tree](https://leetcode.com/problems/encode-n-ary-tree-to-binary-tree) | Hard | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Design`, `Binary Tree`
430 | [Flatten a Multilevel Doubly Linked List](https://leetcode.com/problems/flatten-a-multilevel-doubly-linked-list) | Medium | `Depth-First Search`, `Linked List`, `Doubly-Linked List`
429 | [N-ary Tree Level Order Traversal](https://leetcode.com/problems/n-ary-tree-level-order-traversal) | Medium | `Tree`, `Breadth-First Search`
428 | [Serialize and Deserialize N-ary Tree](https://leetcode.com/problems/serialize-and-deserialize-n-ary-tree) | Hard | `Tree`, `Depth-First Search`, `Breadth-First Search`, `String`
427 | [Construct Quad Tree](https://leetcode.com/problems/construct-quad-tree) | Medium | `Tree`, `Array`, `Divide and Conquer`, `Matrix`
426 | [Convert Binary Search Tree to Sorted Doubly Linked List](https://leetcode.com/problems/convert-binary-search-tree-to-sorted-doubly-linked-list) | Medium | `Stack`, `Tree`, `Depth-First Search`, `Binary Search Tree`, `Linked List`, `Binary Tree`, `Doubly-Linked List`
425 | [Word Squares](https://leetcode.com/problems/word-squares) | Hard | `Trie`, `Array`, `String`, `Backtracking`
424 | [Longest Repeating Character Replacement](https://leetcode.com/problems/longest-repeating-character-replacement) | Medium | `Hash Table`, `String`, `Sliding Window`
423 | [Reconstruct Original Digits from English](https://leetcode.com/problems/reconstruct-original-digits-from-english) | Medium | `Hash Table`, `Math`, `String`
422 | [Valid Word Square](https://leetcode.com/problems/valid-word-square) | Easy | `Array`, `Matrix`
421 | [Maximum XOR of Two Numbers in an Array](https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array) | Medium | `Bit Manipulation`, `Trie`, `Array`, `Hash Table`
420 | [Strong Password Checker](https://leetcode.com/problems/strong-password-checker) | Hard | `Greedy`, `String`, `Heap (Priority Queue)`
419 | [Battleships in a Board](https://leetcode.com/problems/battleships-in-a-board) | Medium | `Depth-First Search`, `Array`, `Matrix`
418 | [Sentence Screen Fitting](https://leetcode.com/problems/sentence-screen-fitting) | Medium | `String`, `Dynamic Programming`
417 | [Pacific Atlantic Water Flow](https://leetcode.com/problems/pacific-atlantic-water-flow) | Medium | `Depth-First Search`, `Breadth-First Search`, `Array`, `Matrix`
416 | [Partition Equal Subset Sum](https://leetcode.com/problems/partition-equal-subset-sum) | Medium | `Array`, `Dynamic Programming`
415 | [Add Strings](https://leetcode.com/problems/add-strings) | Easy | `Math`, `String`, `Simulation`
414 | [Third Maximum Number](https://leetcode.com/problems/third-maximum-number) | Easy | `Array`, `Sorting`
413 | [Arithmetic Slices](https://leetcode.com/problems/arithmetic-slices) | Medium | `Array`, `Dynamic Programming`
411 | [Minimum Unique Word Abbreviation](https://leetcode.com/problems/minimum-unique-word-abbreviation) | Hard | `Bit Manipulation`, `String`, `Backtracking`
410 | [Split Array Largest Sum](https://leetcode.com/problems/split-array-largest-sum) | Hard | `Greedy`, `Array`, `Binary Search`, `Dynamic Programming`
409 | [Longest Palindrome](https://leetcode.com/problems/longest-palindrome) | Easy | `Greedy`, `Hash Table`, `String`
408 | [Valid Word Abbreviation](https://leetcode.com/problems/valid-word-abbreviation) | Easy | `Two Pointers`, `String`
407 | [Trapping Rain Water II](https://leetcode.com/problems/trapping-rain-water-ii) | Hard | `Breadth-First Search`, `Array`, `Matrix`, `Heap (Priority Queue)`
406 | [Queue Reconstruction by Height](https://leetcode.com/problems/queue-reconstruction-by-height) | Medium | `Greedy`, `Array`, `Sorting`
405 | [Convert a Number to Hexadecimal](https://leetcode.com/problems/convert-a-number-to-hexadecimal) | Easy | `Bit Manipulation`, `Math`
404 | [Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
403 | [Frog Jump](https://leetcode.com/problems/frog-jump) | Hard | `Array`, `Dynamic Programming`
402 | [Remove K Digits](https://leetcode.com/problems/remove-k-digits) | Medium | `Stack`, `Greedy`, `String`, `Monotonic Stack`
401 | [Binary Watch](https://leetcode.com/problems/binary-watch) | Easy | `Bit Manipulation`, `Backtracking`
400 | [Nth Digit](https://leetcode.com/problems/nth-digit) | Medium | `Math`, `Binary Search`
399 | [Evaluate Division](https://leetcode.com/problems/evaluate-division) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`, `Array`, `Shortest Path`
398 | [Random Pick Index](https://leetcode.com/problems/random-pick-index) | Medium | `Reservoir Sampling`, `Hash Table`, `Math`, `Randomized`
397 | [Integer Replacement](https://leetcode.com/problems/integer-replacement) | Medium | `Bit Manipulation`, `Memoization`, `Dynamic Programming`
396 | [Rotate Function](https://leetcode.com/problems/rotate-function) | Medium | `Math`, `Dynamic Programming`
395 | [Longest Substring with At Least K Repeating Characters](https://leetcode.com/problems/longest-substring-with-at-least-k-repeating-characters) | Medium | `Hash Table`, `String`, `Divide and Conquer`, `Sliding Window`
394 | [Decode String](https://leetcode.com/problems/decode-string) | Medium | `Stack`, `Recursion`, `String`
393 | [UTF-8 Validation](https://leetcode.com/problems/utf-8-validation) | Medium | `Bit Manipulation`, `Array`
392 | [Is Subsequence](https://leetcode.com/problems/is-subsequence) | Easy | `Two Pointers`, `String`, `Dynamic Programming`
391 | [Perfect Rectangle](https://leetcode.com/problems/perfect-rectangle) | Hard | `Array`, `Line Sweep`
390 | [Elimination Game](https://leetcode.com/problems/elimination-game) | Medium | `Math`
389 | [Find the Difference](https://leetcode.com/problems/find-the-difference) | Easy | `Bit Manipulation`, `Hash Table`, `String`, `Sorting`
388 | [Longest Absolute File Path](https://leetcode.com/problems/longest-absolute-file-path) | Medium | `Stack`, `Depth-First Search`, `String`
385 | [Mini Parser](https://leetcode.com/problems/mini-parser) | Medium | `Stack`, `Depth-First Search`, `String`
383 | [Ransom Note](https://leetcode.com/problems/ransom-note) | Easy | `Hash Table`, `String`, `Counting`
382 | [Linked List Random Node](https://leetcode.com/problems/linked-list-random-node) | Medium | `Reservoir Sampling`, `Linked List`, `Math`, `Randomized`
381 | [Insert Delete GetRandom O(1) - Duplicates allowed](https://leetcode.com/problems/insert-delete-getrandom-o1-duplicates-allowed) | Hard | `Design`, `Array`, `Hash Table`, `Math`, `Randomized`
380 | [Insert Delete GetRandom O(1)](https://leetcode.com/problems/insert-delete-getrandom-o1) | Medium | `Design`, `Array`, `Hash Table`, `Math`, `Randomized`
379 | [Design Phone Directory](https://leetcode.com/problems/design-phone-directory) | Medium | `Design`, `Queue`, `Array`, `Hash Table`, `Linked List`
378 | [Kth Smallest Element in a Sorted Matrix](https://leetcode.com/problems/kth-smallest-element-in-a-sorted-matrix) | Medium | `Array`, `Binary Search`, `Matrix`, `Sorting`, `Heap (Priority Queue)`
377 | [Combination Sum IV](https://leetcode.com/problems/combination-sum-iv) | Medium | `Array`, `Dynamic Programming`
376 | [Wiggle Subsequence](https://leetcode.com/problems/wiggle-subsequence) | Medium | `Greedy`, `Array`, `Dynamic Programming`
375 | [Guess Number Higher or Lower II](https://leetcode.com/problems/guess-number-higher-or-lower-ii) | Medium | `Math`, `Dynamic Programming`, `Game Theory`
374 | [Guess Number Higher or Lower](https://leetcode.com/problems/guess-number-higher-or-lower) | Easy | `Binary Search`, `Interactive`
373 | [Find K Pairs with Smallest Sums](https://leetcode.com/problems/find-k-pairs-with-smallest-sums) | Medium | `Array`, `Heap (Priority Queue)`
372 | [Super Pow](https://leetcode.com/problems/super-pow) | Medium | `Math`, `Divide and Conquer`
371 | [Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers) | Medium | `Bit Manipulation`, `Math`
370 | [Range Addition](https://leetcode.com/problems/range-addition) | Medium | `Array`, `Prefix Sum`
369 | [Plus One Linked List](https://leetcode.com/problems/plus-one-linked-list) | Medium | `Linked List`, `Math`
368 | [Largest Divisible Subset](https://leetcode.com/problems/largest-divisible-subset) | Medium | `Array`, `Math`, `Dynamic Programming`, `Sorting`
366 | [Find Leaves of Binary Tree](https://leetcode.com/problems/find-leaves-of-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
365 | [Water and Jug Problem](https://leetcode.com/problems/water-and-jug-problem) | Medium | `Depth-First Search`, `Breadth-First Search`, `Math`
364 | [Nested List Weight Sum II](https://leetcode.com/problems/nested-list-weight-sum-ii) | Medium | `Stack`, `Depth-First Search`, `Breadth-First Search`
363 | [Max Sum of Rectangle No Larger Than K](https://leetcode.com/problems/max-sum-of-rectangle-no-larger-than-k) | Hard | `Array`, `Binary Search`, `Dynamic Programming`, `Matrix`, `Ordered Set`
362 | [Design Hit Counter](https://leetcode.com/problems/design-hit-counter) | Medium | `Design`, `Queue`, `Array`, `Hash Table`, `Binary Search`
361 | [Bomb Enemy](https://leetcode.com/problems/bomb-enemy) | Medium | `Array`, `Dynamic Programming`, `Matrix`
360 | [Sort Transformed Array](https://leetcode.com/problems/sort-transformed-array) | Medium | `Array`, `Math`, `Two Pointers`, `Sorting`
359 | [Logger Rate Limiter](https://leetcode.com/problems/logger-rate-limiter) | Easy | `Design`, `Hash Table`
358 | [Rearrange String k Distance Apart](https://leetcode.com/problems/rearrange-string-k-distance-apart) | Hard | `Greedy`, `Hash Table`, `String`, `Counting`, `Sorting`, `Heap (Priority Queue)`
357 | [Count Numbers with Unique Digits](https://leetcode.com/problems/count-numbers-with-unique-digits) | Medium | `Math`, `Dynamic Programming`, `Backtracking`
356 | [Line Reflection](https://leetcode.com/problems/line-reflection) | Medium | `Array`, `Hash Table`, `Math`
355 | [Design Twitter](https://leetcode.com/problems/design-twitter) | Medium | `Design`, `Hash Table`, `Linked List`, `Heap (Priority Queue)`
354 | [Russian Doll Envelopes](https://leetcode.com/problems/russian-doll-envelopes) | Hard | `Array`, `Binary Search`, `Dynamic Programming`, `Sorting`
353 | [Design Snake Game](https://leetcode.com/problems/design-snake-game) | Medium | `Design`, `Queue`, `Array`, `Matrix`
352 | [Data Stream as Disjoint Intervals](https://leetcode.com/problems/data-stream-as-disjoint-intervals) | Hard | `Design`, `Binary Search`, `Ordered Set`
351 | [Android Unlock Patterns](https://leetcode.com/problems/android-unlock-patterns) | Medium | `Dynamic Programming`, `Backtracking`
350 | [Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii) | Easy | `Array`, `Hash Table`, `Two Pointers`, `Binary Search`, `Sorting`
349 | [Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays) | Easy | `Array`, `Hash Table`, `Two Pointers`, `Binary Search`, `Sorting`
348 | [Design Tic-Tac-Toe](https://leetcode.com/problems/design-tic-tac-toe) | Medium | `Design`, `Array`, `Hash Table`, `Matrix`
347 | [Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements) | Medium | `Array`, `Hash Table`, `Divide and Conquer`, `Bucket Sort`, `Counting`, `Quickselect`, `Sorting`, `Heap (Priority Queue)`
346 | [Moving Average from Data Stream](https://leetcode.com/problems/moving-average-from-data-stream) | Easy | `Design`, `Queue`, `Array`, `Data Stream`
343 | [Integer Break](https://leetcode.com/problems/integer-break) | Medium | `Math`, `Dynamic Programming`
341 | [Flatten Nested List Iterator](https://leetcode.com/problems/flatten-nested-list-iterator) | Medium | `Stack`, `Tree`, `Depth-First Search`, `Design`, `Queue`, `Iterator`
340 | [Longest Substring with At Most K Distinct Characters](https://leetcode.com/problems/longest-substring-with-at-most-k-distinct-characters) | Medium | `Hash Table`, `String`, `Sliding Window`
339 | [Nested List Weight Sum](https://leetcode.com/problems/nested-list-weight-sum) | Medium | `Depth-First Search`, `Breadth-First Search`
337 | [House Robber III](https://leetcode.com/problems/house-robber-iii) | Medium | `Tree`, `Depth-First Search`, `Dynamic Programming`, `Binary Tree`
336 | [Palindrome Pairs](https://leetcode.com/problems/palindrome-pairs) | Hard | `Trie`, `Array`, `Hash Table`, `String`
335 | [Self Crossing](https://leetcode.com/problems/self-crossing) | Hard | `Geometry`, `Array`, `Math`
334 | [Increasing Triplet Subsequence](https://leetcode.com/problems/increasing-triplet-subsequence) | Medium | `Greedy`, `Array`
333 | [Largest BST Subtree](https://leetcode.com/problems/largest-bst-subtree) | Medium | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Dynamic Programming`, `Binary Tree`
332 | [Reconstruct Itinerary](https://leetcode.com/problems/reconstruct-itinerary) | Medium | `Depth-First Search`, `Graph`, `Eulerian Circuit`
331 | [Verify Preorder Serialization of a Binary Tree](https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree) | Medium | `Stack`, `Tree`, `String`, `Binary Tree`
330 | [Patching Array](https://leetcode.com/problems/patching-array) | Hard | `Greedy`, `Array`
329 | [Longest Increasing Path in a Matrix](https://leetcode.com/problems/longest-increasing-path-in-a-matrix) | Hard | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Topological Sort`, `Memoization`, `Dynamic Programming`
328 | [Odd Even Linked List](https://leetcode.com/problems/odd-even-linked-list) | Medium | `Linked List`
327 | [Count of Range Sum](https://leetcode.com/problems/count-of-range-sum) | Hard | `Binary Indexed Tree`, `Segment Tree`, `Array`, `Binary Search`, `Divide and Conquer`, `Ordered Set`, `Merge Sort`
325 | [Maximum Size Subarray Sum Equals k](https://leetcode.com/problems/maximum-size-subarray-sum-equals-k) | Medium | `Array`, `Hash Table`
324 | [Wiggle Sort II](https://leetcode.com/problems/wiggle-sort-ii) | Medium | `Array`, `Divide and Conquer`, `Quickselect`, `Sorting`
323 | [Number of Connected Components in an Undirected Graph](https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
321 | [Create Maximum Number](https://leetcode.com/problems/create-maximum-number) | Hard | `Stack`, `Greedy`, `Monotonic Stack`
320 | [Generalized Abbreviation](https://leetcode.com/problems/generalized-abbreviation) | Medium | `Bit Manipulation`, `String`, `Backtracking`
319 | [Bulb Switcher](https://leetcode.com/problems/bulb-switcher) | Medium | `Brainteaser`, `Math`
318 | [Maximum Product of Word Lengths](https://leetcode.com/problems/maximum-product-of-word-lengths) | Medium | `Bit Manipulation`, `Array`, `String`
317 | [Shortest Distance from All Buildings](https://leetcode.com/problems/shortest-distance-from-all-buildings) | Hard | `Breadth-First Search`, `Array`, `Matrix`
316 | [Remove Duplicate Letters](https://leetcode.com/problems/remove-duplicate-letters) | Medium | `Stack`, `Greedy`, `String`, `Monotonic Stack`
315 | [Count of Smaller Numbers After Self](https://leetcode.com/problems/count-of-smaller-numbers-after-self) | Hard | `Binary Indexed Tree`, `Segment Tree`, `Array`, `Binary Search`, `Divide and Conquer`, `Ordered Set`, `Merge Sort`
314 | [Binary Tree Vertical Order Traversal](https://leetcode.com/problems/binary-tree-vertical-order-traversal) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Hash Table`, `Binary Tree`
312 | [Burst Balloons](https://leetcode.com/problems/burst-balloons) | Hard | `Array`, `Dynamic Programming`
311 | [Sparse Matrix Multiplication](https://leetcode.com/problems/sparse-matrix-multiplication) | Medium | `Array`, `Hash Table`, `Matrix`
310 | [Minimum Height Trees](https://leetcode.com/problems/minimum-height-trees) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Topological Sort`
309 | [Best Time to Buy and Sell Stock with Cooldown](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-with-cooldown) | Medium | `Array`, `Dynamic Programming`
308 | [Range Sum Query 2D - Mutable](https://leetcode.com/problems/range-sum-query-2d-mutable) | Hard | `Design`, `Binary Indexed Tree`, `Segment Tree`, `Array`, `Matrix`
307 | [Range Sum Query - Mutable](https://leetcode.com/problems/range-sum-query-mutable) | Medium | `Design`, `Binary Indexed Tree`, `Segment Tree`, `Array`
306 | [Additive Number](https://leetcode.com/problems/additive-number) | Medium | `String`, `Backtracking`
305 | [Number of Islands II](https://leetcode.com/problems/number-of-islands-ii) | Hard | `Union Find`, `Array`
304 | [Range Sum Query 2D - Immutable](https://leetcode.com/problems/range-sum-query-2d-immutable) | Medium | `Design`, `Array`, `Matrix`, `Prefix Sum`
303 | [Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable) | Easy | `Design`, `Array`, `Prefix Sum`
302 | [Smallest Rectangle Enclosing Black Pixels](https://leetcode.com/problems/smallest-rectangle-enclosing-black-pixels) | Hard | `Depth-First Search`, `Breadth-First Search`, `Array`, `Binary Search`, `Matrix`
301 | [Remove Invalid Parentheses](https://leetcode.com/problems/remove-invalid-parentheses) | Hard | `Breadth-First Search`, `String`, `Backtracking`
300 | [Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence) | Medium | `Array`, `Binary Search`, `Dynamic Programming`
299 | [Bulls and Cows](https://leetcode.com/problems/bulls-and-cows) | Medium | `Hash Table`, `String`, `Counting`
298 | [Binary Tree Longest Consecutive Sequence](https://leetcode.com/problems/binary-tree-longest-consecutive-sequence) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
297 | [Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree) | Hard | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Design`, `String`, `Binary Tree`
296 | [Best Meeting Point](https://leetcode.com/problems/best-meeting-point) | Hard | `Array`, `Math`, `Matrix`, `Sorting`
295 | [Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream) | Hard | `Design`, `Two Pointers`, `Data Stream`, `Sorting`, `Heap (Priority Queue)`
294 | [Flip Game II](https://leetcode.com/problems/flip-game-ii) | Medium | `Memoization`, `Math`, `Dynamic Programming`, `Backtracking`, `Game Theory`
293 | [Flip Game](https://leetcode.com/problems/flip-game) | Easy | `String`
292 | [Nim Game](https://leetcode.com/problems/nim-game) | Easy | `Brainteaser`, `Math`, `Game Theory`
291 | [Word Pattern II](https://leetcode.com/problems/word-pattern-ii) | Medium | `Hash Table`, `String`, `Backtracking`
290 | [Word Pattern](https://leetcode.com/problems/word-pattern) | Easy | `Hash Table`, `String`
289 | [Game of Life](https://leetcode.com/problems/game-of-life) | Medium | `Array`, `Matrix`, `Simulation`
288 | [Unique Word Abbreviation](https://leetcode.com/problems/unique-word-abbreviation) | Medium | `Design`, `Array`, `Hash Table`, `String`
287 | [Find the Duplicate Number](https://leetcode.com/problems/find-the-duplicate-number) | Medium | `Bit Manipulation`, `Array`, `Two Pointers`, `Binary Search`
286 | [Walls and Gates](https://leetcode.com/problems/walls-and-gates) | Medium | `Breadth-First Search`, `Array`, `Matrix`
285 | [Inorder Successor in BST](https://leetcode.com/problems/inorder-successor-in-bst) | Medium | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
284 | [Peeking Iterator](https://leetcode.com/problems/peeking-iterator) | Medium | `Design`, `Array`, `Iterator`
283 | [Move Zeroes](https://leetcode.com/problems/move-zeroes) | Easy | `Array`, `Two Pointers`
282 | [Expression Add Operators](https://leetcode.com/problems/expression-add-operators) | Hard | `Math`, `String`, `Backtracking`
281 | [Zigzag Iterator](https://leetcode.com/problems/zigzag-iterator) | Medium | `Design`, `Queue`, `Array`, `Iterator`
280 | [Wiggle Sort](https://leetcode.com/problems/wiggle-sort) | Medium | `Greedy`, `Array`, `Sorting`
279 | [Perfect Squares](https://leetcode.com/problems/perfect-squares) | Medium | `Breadth-First Search`, `Math`, `Dynamic Programming`
278 | [First Bad Version](https://leetcode.com/problems/first-bad-version) | Easy | `Binary Search`, `Interactive`
277 | [Find the Celebrity](https://leetcode.com/problems/find-the-celebrity) | Medium | `Greedy`, `Graph`, `Two Pointers`, `Interactive`
276 | [Paint Fence](https://leetcode.com/problems/paint-fence) | Medium | `Dynamic Programming`
274 | [H-Index](https://leetcode.com/problems/h-index) | Medium | `Array`, `Counting Sort`, `Sorting`
273 | [Integer to English Words](https://leetcode.com/problems/integer-to-english-words) | Hard | `Recursion`, `Math`, `String`
272 | [Closest Binary Search Tree Value II](https://leetcode.com/problems/closest-binary-search-tree-value-ii) | Hard | `Stack`, `Tree`, `Depth-First Search`, `Binary Search Tree`, `Two Pointers`, `Binary Tree`, `Heap (Priority Queue)`
271 | [Encode and Decode Strings](https://leetcode.com/problems/encode-and-decode-strings) | Medium | `Design`, `Array`, `String`
270 | [Closest Binary Search Tree Value](https://leetcode.com/problems/closest-binary-search-tree-value) | Easy | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Search`, `Binary Tree`
269 | [Alien Dictionary](https://leetcode.com/problems/alien-dictionary) | Hard | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Topological Sort`, `Array`, `String`
268 | [Missing Number](https://leetcode.com/problems/missing-number) | Easy | `Bit Manipulation`, `Array`, `Hash Table`, `Math`, `Sorting`
267 | [Palindrome Permutation II](https://leetcode.com/problems/palindrome-permutation-ii) | Medium | `Hash Table`, `String`, `Backtracking`
266 | [Palindrome Permutation](https://leetcode.com/problems/palindrome-permutation) | Easy | `Bit Manipulation`, `Hash Table`, `String`
265 | [Paint House II](https://leetcode.com/problems/paint-house-ii) | Hard | `Array`, `Dynamic Programming`
262 | [Trips and Users](https://leetcode.com/problems/trips-and-users) | Hard | `Database`
261 | [Graph Valid Tree](https://leetcode.com/problems/graph-valid-tree) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Graph`
260 | [Single Number III](https://leetcode.com/problems/single-number-iii) | Medium | `Bit Manipulation`, `Array`
259 | [3Sum Smaller](https://leetcode.com/problems/3sum-smaller) | Medium | `Array`, `Two Pointers`, `Binary Search`, `Sorting`
258 | [Add Digits](https://leetcode.com/problems/add-digits) | Easy | `Math`, `Number Theory`, `Simulation`
257 | [Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths) | Easy | `Tree`, `Depth-First Search`, `String`, `Binary Tree`
256 | [Paint House](https://leetcode.com/problems/paint-house) | Medium | `Array`, `Dynamic Programming`
255 | [Verify Preorder Sequence in Binary Search Tree](https://leetcode.com/problems/verify-preorder-sequence-in-binary-search-tree) | Medium | `Stack`, `Tree`, `Binary Search Tree`, `Recursion`, `Binary Tree`, `Monotonic Stack`
254 | [Factor Combinations](https://leetcode.com/problems/factor-combinations) | Medium | `Array`, `Backtracking`
253 | [Meeting Rooms II](https://leetcode.com/problems/meeting-rooms-ii) | Medium | `Greedy`, `Array`, `Two Pointers`, `Sorting`, `Heap (Priority Queue)`
252 | [Meeting Rooms](https://leetcode.com/problems/meeting-rooms) | Easy | `Array`, `Sorting`
251 | [Flatten 2D Vector](https://leetcode.com/problems/flatten-2d-vector) | Medium | `Design`, `Array`, `Two Pointers`, `Iterator`
250 | [Count Univalue Subtrees](https://leetcode.com/problems/count-univalue-subtrees) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
249 | [Group Shifted Strings](https://leetcode.com/problems/group-shifted-strings) | Medium | `Array`, `Hash Table`, `String`
248 | [Strobogrammatic Number III](https://leetcode.com/problems/strobogrammatic-number-iii) | Hard | `Recursion`, `Array`, `String`
247 | [Strobogrammatic Number II](https://leetcode.com/problems/strobogrammatic-number-ii) | Medium | `Recursion`, `Array`, `String`
246 | [Strobogrammatic Number](https://leetcode.com/problems/strobogrammatic-number) | Easy | `Hash Table`, `Two Pointers`, `String`
245 | [Shortest Word Distance III](https://leetcode.com/problems/shortest-word-distance-iii) | Medium | `Array`, `String`
244 | [Shortest Word Distance II](https://leetcode.com/problems/shortest-word-distance-ii) | Medium | `Design`, `Array`, `Hash Table`, `Two Pointers`, `String`
243 | [Shortest Word Distance](https://leetcode.com/problems/shortest-word-distance) | Easy | `Array`, `String`
242 | [Valid Anagram](https://leetcode.com/problems/valid-anagram) | Easy | `Hash Table`, `String`, `Sorting`
241 | [Different Ways to Add Parentheses](https://leetcode.com/problems/different-ways-to-add-parentheses) | Medium | `Recursion`, `Memoization`, `Math`, `String`, `Dynamic Programming`
240 | [Search a 2D Matrix II](https://leetcode.com/problems/search-a-2d-matrix-ii) | Medium | `Array`, `Binary Search`, `Divide and Conquer`, `Matrix`
238 | [Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self) | Medium | `Array`, `Prefix Sum`
237 | [Delete Node in a Linked List](https://leetcode.com/problems/delete-node-in-a-linked-list) | Easy | `Linked List`
236 | [Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
235 | [Lowest Common Ancestor of a Binary Search Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree) | Easy | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
234 | [Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list) | Easy | `Stack`, `Recursion`, `Linked List`, `Two Pointers`
233 | [Number of Digit One](https://leetcode.com/problems/number-of-digit-one) | Hard | `Recursion`, `Math`, `Dynamic Programming`
232 | [Implement Queue using Stacks](https://leetcode.com/problems/implement-queue-using-stacks) | Easy | `Stack`, `Design`, `Queue`
230 | [Kth Smallest Element in a BST](https://leetcode.com/problems/kth-smallest-element-in-a-bst) | Medium | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
229 | [Majority Element II](https://leetcode.com/problems/majority-element-ii) | Medium | `Array`, `Hash Table`, `Counting`, `Sorting`
228 | [Summary Ranges](https://leetcode.com/problems/summary-ranges) | Easy | `Array`
227 | [Basic Calculator II](https://leetcode.com/problems/basic-calculator-ii) | Medium | `Stack`, `Math`, `String`
226 | [Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
225 | [Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues) | Easy | `Stack`, `Design`, `Queue`
224 | [Basic Calculator](https://leetcode.com/problems/basic-calculator) | Hard | `Stack`, `Recursion`, `Math`, `String`
223 | [Rectangle Area](https://leetcode.com/problems/rectangle-area) | Medium | `Geometry`, `Math`
222 | [Count Complete Tree Nodes](https://leetcode.com/problems/count-complete-tree-nodes) | Medium | `Tree`, `Depth-First Search`, `Binary Search`, `Binary Tree`
221 | [Maximal Square](https://leetcode.com/problems/maximal-square) | Medium | `Array`, `Dynamic Programming`, `Matrix`
218 | [The Skyline Problem](https://leetcode.com/problems/the-skyline-problem) | Hard | `Binary Indexed Tree`, `Segment Tree`, `Array`, `Divide and Conquer`, `Ordered Set`, `Line Sweep`, `Heap (Priority Queue)`
216 | [Combination Sum III](https://leetcode.com/problems/combination-sum-iii) | Medium | `Array`, `Backtracking`
213 | [House Robber II](https://leetcode.com/problems/house-robber-ii) | Medium | `Array`, `Dynamic Programming`
212 | [Word Search II](https://leetcode.com/problems/word-search-ii) | Hard | `Trie`, `Array`, `String`, `Backtracking`, `Matrix`
211 | [Design Add and Search Words Data Structure](https://leetcode.com/problems/design-add-and-search-words-data-structure) | Medium | `Depth-First Search`, `Design`, `Trie`, `String`
210 | [Course Schedule II](https://leetcode.com/problems/course-schedule-ii) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Topological Sort`
209 | [Minimum Size Subarray Sum](https://leetcode.com/problems/minimum-size-subarray-sum) | Medium | `Array`, `Binary Search`, `Prefix Sum`, `Sliding Window`
208 | [Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree) | Medium | `Design`, `Trie`, `Hash Table`, `String`
207 | [Course Schedule](https://leetcode.com/problems/course-schedule) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Topological Sort`
206 | [Reverse Linked List](https://leetcode.com/problems/reverse-linked-list) | Easy | `Recursion`, `Linked List`
205 | [Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings) | Easy | `Hash Table`, `String`
203 | [Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements) | Easy | `Recursion`, `Linked List`
201 | [Bitwise AND of Numbers Range](https://leetcode.com/problems/bitwise-and-of-numbers-range) | Medium | `Bit Manipulation`
199 | [Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
197 | [Rising Temperature](https://leetcode.com/problems/rising-temperature) | Easy | `Database`
196 | [Delete Duplicate Emails](https://leetcode.com/problems/delete-duplicate-emails) | Easy | `Database`
195 | [Tenth Line](https://leetcode.com/problems/tenth-line) | Easy | `Shell`
194 | [Transpose File](https://leetcode.com/problems/transpose-file) | Medium | `Shell`
193 | [Valid Phone Numbers](https://leetcode.com/problems/valid-phone-numbers) | Easy | `Shell`
192 | [Word Frequency](https://leetcode.com/problems/word-frequency) | Medium | `Shell`
190 | [Reverse Bits](https://leetcode.com/problems/reverse-bits) | Easy | `Bit Manipulation`, `Divide and Conquer`
188 | [Best Time to Buy and Sell Stock IV](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iv) | Hard | `Array`, `Dynamic Programming`
187 | [Repeated DNA Sequences](https://leetcode.com/problems/repeated-dna-sequences) | Medium | `Bit Manipulation`, `Hash Table`, `String`, `Sliding Window`, `Hash Function`, `Rolling Hash`
186 | [Reverse Words in a String II](https://leetcode.com/problems/reverse-words-in-a-string-ii) | Medium | `Two Pointers`, `String`
185 | [Department Top Three Salaries](https://leetcode.com/problems/department-top-three-salaries) | Hard | `Database`
184 | [Department Highest Salary](https://leetcode.com/problems/department-highest-salary) | Medium | `Database`
183 | [Customers Who Never Order](https://leetcode.com/problems/customers-who-never-order) | Easy | `Database`
182 | [Duplicate Emails](https://leetcode.com/problems/duplicate-emails) | Easy | `Database`
181 | [Employees Earning More Than Their Managers](https://leetcode.com/problems/employees-earning-more-than-their-managers) | Easy | `Database`
180 | [Consecutive Numbers](https://leetcode.com/problems/consecutive-numbers) | Medium | `Database`
178 | [Rank Scores](https://leetcode.com/problems/rank-scores) | Medium | `Database`
177 | [Nth Highest Salary](https://leetcode.com/problems/nth-highest-salary) | Medium | `Database`
176 | [Second Highest Salary](https://leetcode.com/problems/second-highest-salary) | Medium | `Database`
175 | [Combine Two Tables](https://leetcode.com/problems/combine-two-tables) | Easy | `Database`
174 | [Dungeon Game](https://leetcode.com/problems/dungeon-game) | Hard | `Array`, `Dynamic Programming`, `Matrix`
172 | [Factorial Trailing Zeroes](https://leetcode.com/problems/factorial-trailing-zeroes) | Medium | `Math`
170 | [Two Sum III - Data structure design](https://leetcode.com/problems/two-sum-iii-data-structure-design) | Easy | `Design`, `Array`, `Hash Table`, `Two Pointers`, `Data Stream`
169 | [Majority Element](https://leetcode.com/problems/majority-element) | Easy | `Array`, `Hash Table`, `Divide and Conquer`, `Counting`, `Sorting`
167 | [Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted) | Easy | `Array`, `Two Pointers`, `Binary Search`
166 | [Fraction to Recurring Decimal](https://leetcode.com/problems/fraction-to-recurring-decimal) | Medium | `Hash Table`, `Math`, `String`
164 | [Maximum Gap](https://leetcode.com/problems/maximum-gap) | Hard | `Array`, `Bucket Sort`, `Radix Sort`, `Sorting`
163 | [Missing Ranges](https://leetcode.com/problems/missing-ranges) | Easy | `Array`
162 | [Find Peak Element](https://leetcode.com/problems/find-peak-element) | Medium | `Array`, `Binary Search`
161 | [One Edit Distance](https://leetcode.com/problems/one-edit-distance) | Medium | `Two Pointers`, `String`
160 | [Intersection of Two Linked Lists](https://leetcode.com/problems/intersection-of-two-linked-lists) | Easy | `Hash Table`, `Linked List`, `Two Pointers`
159 | [Longest Substring with At Most Two Distinct Characters](https://leetcode.com/problems/longest-substring-with-at-most-two-distinct-characters) | Medium | `Hash Table`, `String`, `Sliding Window`
158 | [Read N Characters Given Read4 II - Call multiple times](https://leetcode.com/problems/read-n-characters-given-read4-ii-call-multiple-times) | Hard | `String`, `Interactive`, `Simulation`
157 | [Read N Characters Given Read4](https://leetcode.com/problems/read-n-characters-given-read4) | Easy | `String`, `Interactive`, `Simulation`
156 | [Binary Tree Upside Down](https://leetcode.com/problems/binary-tree-upside-down) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
155 | [Min Stack](https://leetcode.com/problems/min-stack) | Easy | `Stack`, `Design`
154 | [Find Minimum in Rotated Sorted Array II](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array-ii) | Hard | `Array`, `Binary Search`
153 | [Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array) | Medium | `Array`, `Binary Search`
152 | [Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray) | Medium | `Array`, `Dynamic Programming`
150 | [Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation) | Medium | `Stack`, `Array`, `Math`
149 | [Max Points on a Line](https://leetcode.com/problems/max-points-on-a-line) | Hard | `Geometry`, `Hash Table`, `Math`
148 | [Sort List](https://leetcode.com/problems/sort-list) | Medium | `Linked List`, `Two Pointers`, `Divide and Conquer`, `Sorting`, `Merge Sort`
147 | [Insertion Sort List](https://leetcode.com/problems/insertion-sort-list) | Medium | `Linked List`, `Sorting`
143 | [Reorder List](https://leetcode.com/problems/reorder-list) | Medium | `Stack`, `Recursion`, `Linked List`, `Two Pointers`
142 | [Linked List Cycle II](https://leetcode.com/problems/linked-list-cycle-ii) | Medium | `Hash Table`, `Linked List`, `Two Pointers`
141 | [Linked List Cycle](https://leetcode.com/problems/linked-list-cycle) | Easy | `Hash Table`, `Linked List`, `Two Pointers`
140 | [Word Break II](https://leetcode.com/problems/word-break-ii) | Hard | `Trie`, `Memoization`, `Hash Table`, `String`, `Dynamic Programming`, `Backtracking`
139 | [Word Break](https://leetcode.com/problems/word-break) | Medium | `Trie`, `Memoization`, `Hash Table`, `String`, `Dynamic Programming`
138 | [Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer) | Medium | `Hash Table`, `Linked List`
137 | [Single Number II](https://leetcode.com/problems/single-number-ii) | Medium | `Bit Manipulation`, `Array`
135 | [Candy](https://leetcode.com/problems/candy) | Hard | `Greedy`, `Array`
134 | [Gas Station](https://leetcode.com/problems/gas-station) | Medium | `Greedy`, `Array`
133 | [Clone Graph](https://leetcode.com/problems/clone-graph) | Medium | `Depth-First Search`, `Breadth-First Search`, `Graph`, `Hash Table`
132 | [Palindrome Partitioning II](https://leetcode.com/problems/palindrome-partitioning-ii) | Hard | `String`, `Dynamic Programming`
131 | [Palindrome Partitioning](https://leetcode.com/problems/palindrome-partitioning) | Medium | `String`, `Dynamic Programming`, `Backtracking`
130 | [Surrounded Regions](https://leetcode.com/problems/surrounded-regions) | Medium | `Depth-First Search`, `Breadth-First Search`, `Union Find`, `Array`, `Matrix`
129 | [Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers) | Medium | `Tree`, `Depth-First Search`, `Binary Tree`
128 | [Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence) | Medium | `Union Find`, `Array`, `Hash Table`
127 | [Word Ladder](https://leetcode.com/problems/word-ladder) | Hard | `Breadth-First Search`, `Hash Table`, `String`
126 | [Word Ladder II](https://leetcode.com/problems/word-ladder-ii) | Hard | `Breadth-First Search`, `Hash Table`, `String`, `Backtracking`
124 | [Binary Tree Maximum Path Sum](https://leetcode.com/problems/binary-tree-maximum-path-sum) | Hard | `Tree`, `Depth-First Search`, `Dynamic Programming`, `Binary Tree`
123 | [Best Time to Buy and Sell Stock III](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iii) | Hard | `Array`, `Dynamic Programming`
117 | [Populating Next Right Pointers in Each Node II](https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
116 | [Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node) | Medium | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
115 | [Distinct Subsequences](https://leetcode.com/problems/distinct-subsequences) | Hard | `String`, `Dynamic Programming`
113 | [Path Sum II](https://leetcode.com/problems/path-sum-ii) | Medium | `Tree`, `Depth-First Search`, `Backtracking`, `Binary Tree`
112 | [Path Sum](https://leetcode.com/problems/path-sum) | Easy | `Tree`, `Depth-First Search`, `Binary Tree`
111 | [Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
110 | [Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Binary Tree`
107 | [Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii) | Medium | `Tree`, `Breadth-First Search`, `Binary Tree`
106 | [Construct Binary Tree from Inorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal) | Medium | `Tree`, `Array`, `Hash Table`, `Divide and Conquer`, `Binary Tree`
105 | [Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal) | Medium | `Tree`, `Array`, `Hash Table`, `Divide and Conquer`, `Binary Tree`
104 | [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
103 | [Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal) | Medium | `Tree`, `Breadth-First Search`, `Binary Tree`
102 | [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal) | Medium | `Tree`, `Breadth-First Search`, `Binary Tree`
101 | [Symmetric Tree](https://leetcode.com/problems/symmetric-tree) | Easy | `Tree`, `Depth-First Search`, `Breadth-First Search`, `Binary Tree`
99 | [Recover Binary Search Tree](https://leetcode.com/problems/recover-binary-search-tree) | Medium | `Tree`, `Depth-First Search`, `Binary Search Tree`, `Binary Tree`
96 | [Unique Binary Search Trees](https://leetcode.com/problems/unique-binary-search-trees) | Medium | `Tree`, `Binary Search Tree`, `Math`, `Dynamic Programming`, `Binary Tree`
95 | [Unique Binary Search Trees II](https://leetcode.com/problems/unique-binary-search-trees-ii) | Medium | `Tree`, `Binary Search Tree`, `Dynamic Programming`, `Backtracking`, `Binary Tree`
93 | [Restore IP Addresses](https://leetcode.com/problems/restore-ip-addresses) | Medium | `String`, `Backtracking`
92 | [Reverse Linked List II](https://leetcode.com/problems/reverse-linked-list-ii) | Medium | `Linked List`
91 | [Decode Ways](https://leetcode.com/problems/decode-ways) | Medium | `String`, `Dynamic Programming`
90 | [Subsets II](https://leetcode.com/problems/subsets-ii) | Medium | `Bit Manipulation`, `Array`, `Backtracking`
89 | [Gray Code](https://leetcode.com/problems/gray-code) | Medium | `Bit Manipulation`, `Math`, `Backtracking`
88 | [Merge Sorted Array](https://leetcode.com/problems/merge-sorted-array) | Easy | `Array`, `Two Pointers`, `Sorting`
87 | [Scramble String](https://leetcode.com/problems/scramble-string) | Hard | `String`, `Dynamic Programming`
86 | [Partition List](https://leetcode.com/problems/partition-list) | Medium | `Linked List`, `Two Pointers`
85 | [Maximal Rectangle](https://leetcode.com/problems/maximal-rectangle) | Hard | `Stack`, `Array`, `Dynamic Programming`, `Matrix`, `Monotonic Stack`
84 | [Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram) | Hard | `Stack`, `Array`, `Monotonic Stack`
82 | [Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii) | Medium | `Linked List`, `Two Pointers`
81 | [Search in Rotated Sorted Array II](https://leetcode.com/problems/search-in-rotated-sorted-array-ii) | Medium | `Array`, `Binary Search`
80 | [Remove Duplicates from Sorted Array II](https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii) | Medium | `Array`, `Two Pointers`
79 | [Word Search](https://leetcode.com/problems/word-search) | Medium | `Array`, `Backtracking`, `Matrix`
77 | [Combinations](https://leetcode.com/problems/combinations) | Medium | `Array`, `Backtracking`
76 | [Minimum Window Substring](https://leetcode.com/problems/minimum-window-substring) | Hard | `Hash Table`, `String`, `Sliding Window`
75 | [Sort Colors](https://leetcode.com/problems/sort-colors) | Medium | `Array`, `Two Pointers`, `Sorting`
73 | [Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes) | Medium | `Array`, `Hash Table`, `Matrix`
72 | [Edit Distance](https://leetcode.com/problems/edit-distance) | Hard | `String`, `Dynamic Programming`
71 | [Simplify Path](https://leetcode.com/problems/simplify-path) | Medium | `Stack`, `String`
70 | [Climbing Stairs](https://leetcode.com/problems/climbing-stairs) | Easy | `Memoization`, `Math`, `Dynamic Programming`
68 | [Text Justification](https://leetcode.com/problems/text-justification) | Hard | `String`, `Simulation`
67 | [Add Binary](https://leetcode.com/problems/add-binary) | Easy | `Bit Manipulation`, `Math`, `String`, `Simulation`
66 | [Plus One](https://leetcode.com/problems/plus-one) | Easy | `Array`, `Math`
65 | [Valid Number](https://leetcode.com/problems/valid-number) | Hard | `String`
60 | [Permutation Sequence](https://leetcode.com/problems/permutation-sequence) | Hard | `Recursion`, `Math`
58 | [Length of Last Word](https://leetcode.com/problems/length-of-last-word) | Easy | `String`
55 | [Jump Game](https://leetcode.com/problems/jump-game) | Medium | `Greedy`, `Array`, `Dynamic Programming`
53 | [Maximum Subarray](https://leetcode.com/problems/maximum-subarray) | Easy | `Array`, `Divide and Conquer`, `Dynamic Programming`
52 | [N-Queens II](https://leetcode.com/problems/n-queens-ii) | Hard | `Backtracking`
48 | [Rotate Image](https://leetcode.com/problems/rotate-image) | Medium | `Array`, `Math`, `Matrix`
45 | [Jump Game II](https://leetcode.com/problems/jump-game-ii) | Medium | `Greedy`, `Array`, `Dynamic Programming`
44 | [Wildcard Matching](https://leetcode.com/problems/wildcard-matching) | Hard | `Greedy`, `Recursion`, `String`, `Dynamic Programming`
43 | [Multiply Strings](https://leetcode.com/problems/multiply-strings) | Medium | `Math`, `String`, `Simulation`
42 | [Trapping Rain Water](https://leetcode.com/problems/trapping-rain-water) | Hard | `Stack`, `Array`, `Two Pointers`, `Dynamic Programming`, `Monotonic Stack`
41 | [First Missing Positive](https://leetcode.com/problems/first-missing-positive) | Hard | `Array`, `Hash Table`
40 | [Combination Sum II](https://leetcode.com/problems/combination-sum-ii) | Medium | `Array`, `Backtracking`
39 | [Combination Sum](https://leetcode.com/problems/combination-sum) | Medium | `Array`, `Backtracking`
38 | [Count and Say](https://leetcode.com/problems/count-and-say) | Medium | `String`
35 | [Search Insert Position](https://leetcode.com/problems/search-insert-position) | Easy | `Array`, `Binary Search`
32 | [Longest Valid Parentheses](https://leetcode.com/problems/longest-valid-parentheses) | Hard | `Stack`, `String`, `Dynamic Programming`
30 | [Substring with Concatenation of All Words](https://leetcode.com/problems/substring-with-concatenation-of-all-words) | Hard | `Hash Table`, `String`, `Sliding Window`
29 | [Divide Two Integers](https://leetcode.com/problems/divide-two-integers) | Medium | `Bit Manipulation`, `Math`
28 | [Implement strStr()](https://leetcode.com/problems/implement-strstr) | Easy | `Two Pointers`, `String`, `String Matching`
27 | [Remove Element](https://leetcode.com/problems/remove-element) | Easy | `Array`, `Two Pointers`
25 | [Reverse Nodes in k-Group](https://leetcode.com/problems/reverse-nodes-in-k-group) | Hard | `Recursion`, `Linked List`
24 | [Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs) | Medium | `Recursion`, `Linked List`
19 | [Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list) | Medium | `Linked List`, `Two Pointers`
18 | [4Sum](https://leetcode.com/problems/4sum) | Medium | `Array`, `Two Pointers`, `Sorting`
16 | [3Sum Closest](https://leetcode.com/problems/3sum-closest) | Medium | `Array`, `Two Pointers`, `Sorting`
14 | [Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix) | Easy | `String`
13 | [Roman to Integer](https://leetcode.com/problems/roman-to-integer) | Easy | `Hash Table`, `Math`, `String`
10 | [Regular Expression Matching](https://leetcode.com/problems/regular-expression-matching) | Hard | `Recursion`, `String`, `Dynamic Programming`