https://github.com/guobinhit/myleetcode

♨️ Detailed Java & Go & Python solution of LeetCode.
https://github.com/guobinhit/myleetcode

algorithm interview leetcode list queue search sort stack string tree

Last synced: 2 months ago
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♨️ Detailed Java & Go & Python solution of LeetCode.

• Host: GitHub
• URL: https://github.com/guobinhit/myleetcode
• Owner: guobinhit
• License: mit
• Created: 2018-08-21T23:49:58.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2023-01-09T03:36:45.000Z (over 3 years ago)
• Last Synced: 2025-04-06T16:48:46.917Z (about 1 year ago)
• Topics: algorithm, interview, leetcode, list, queue, search, sort, stack, string, tree
• Language: Java
• Homepage: https://guobinhit.github.io/myleetcode/
• Size: 1.39 MB
• Stars: 52
• Watchers: 4
• Forks: 35
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE

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README

          
# myleetcode

![author](https://img.shields.io/badge/author-chariesgavin-blueviolet.svg)![issues](https://img.shields.io/github/issues/guobinhit/myleetcode.svg)![stars](https://img.shields.io/github/stars/guobinhit/myleetcode.svg)![forks](	https://img.shields.io/github/forks/guobinhit/myleetcode.svg)![license](https://img.shields.io/github/license/guobinhit/myleetcode.svg)

My LeetCode Solutions!

## Contributing

Contributions are very welcome!

If you see an problem that you'd like to see fixed, the best way to make it happen is to help out by submitting a pull request implementing it. Refer to the [CONTRIBUTING.md](https://github.com/guobinhit/myleetcode/blob/master/CONTRIBUTING.md) file for more details about the workflow. 

You can also ask for problem solving ideas and discuss in GitHub issues directly.

## INDEX

- **Learn**

  - [Array and String](#array-and-string)

  - [Queue & Stack](#queue--stack)

  - [Linked List](#linked-list)

  - [Hash Table](#hash-table)

  - [Binary Search](#binary-search)

  - [Binary Tree](#binary-tree)

  - [Binary Search Tree](#binary-search-tree)

  - [N-ary Tree](#n-ary-tree)

  - [Trie (Prefix Tree)](#trie-prefix-tree)

  - [Decision Tree](#decision-tree)

  - [Recursion I](#recursion-i)

  - [Recursion II](#recursion-ii)

  - [Concurrency](#concurrency)

  - [Others](#others)

  - [Shell](#shell)

  - [Database](#database)

  - [Sort Algorithm](#sort-algorithm)

  - [Search Algorithm](#search-algorithm)

- **Interview**

  - [Top Interview Questions](#top-interview-questions)

    - [Easy Collection](#easy-collection)

    - [Medium Collection](#medium-collection)

    - [Hard Collection](#hard-collection)

## Learn

### Array and String

|  #  |      Title     |   Solutions  |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|14|[Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_14.java) & Python|Easy| Introduction to String

|26|[Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_26.java) & Python|Easy| Conclusion

|27|[Remove Element](https://leetcode.com/problems/remove-element/)|[Java](../master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_27.java) & [Go](../master/codes/go/leetcodes/learn/array_and_string/27.go)|Easy| Two-Pointer Technique

|28|[Implement strStr()](https://leetcode.com/problems/implement-strstr/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_28.java) & Python|Easy| Introduction to String

|54|[Spiral Matrix](https://leetcode.com/problems/spiral-matrix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_54.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_54.py)|Medium| Introduction to 2D Array

|66|[Plus One](https://leetcode.com/problems/plus-one/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_66.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_66.py)|Easy| Introduction to Array

|67|[Add Binary](https://leetcode.com/problems/add-binary/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_67.java) & Python|Easy| Introduction to String

|118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_118.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_118.py)| Easy| Introduction to 2D Array

|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_119.java) & Python| Easy| Conclusion

|151|[Reverse Words in a String](https://leetcode.com/problems/pascals-triangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_151.java) & Python| Medium| Conclusion

|167|[Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_167.java) & Python| Easy| Two-Pointer Technique

|189|[Rotate Array](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_189.java) & Python| Easy| Conclusion

|209|[Minimum Size Subarray Sum](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_209.java) & Python| Medium| Two-Pointer Technique

|283|[Move Zeroes](https://leetcode.com/problems/move-zeroes/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_283.java) & Python| Easy| Conclusion

|344|[Reverse String](https://leetcode.com/problems/reverse-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_344.java) & Python| Easy| Two-Pointer Technique

|485|[Max Consecutive Ones](https://leetcode.com/problems/diagonal-traverse/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_485.java) & Python |Easy| Two-Pointer Technique

|498|[Diagonal Traverse](https://leetcode.com/problems/diagonal-traverse/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_498.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_498.py) |Medium| Introduction to 2D Array

|557|[Reverse Words in a String III](https://leetcode.com/problems/reverse-words-in-a-string-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_557.java) & Python |Easy| Conclusion

|561|[Array Partition I](https://leetcode.com/problems/array-partition-i/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_561.java)  & Python|Easy| Two-Pointer Technique

|724|[Find Pivot Index](https://leetcode.com/problems/find-pivot-index/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_724.java)  & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_724.py)| Easy | Introduction to Array

|747|[Largest Number Greater Than Twice of Others](https://leetcode.com/problems/largest-number-at-least-twice-of-others/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_747.java)  & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_747.py)| Easy| Introduction to Array

### Queue & Stack

|  #  |      Title     |   Solutions   |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|20|[Valid Parentheses](https://leetcode.com/problems/valid-parentheses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_20.java) & Python|Easy| Stack: Last-in-first-out Data Structure

|133|[Clone Graph](https://leetcode.com/problems/clone-graph/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_133.java) & Python|Medium| Stack and DFS

|150|[Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_150.java) & Python|Medium| Stack: Last-in-first-out Data Structure

|155|[Min Stack](https://leetcode.com/problems/min-stack/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_155.java) & Python|Easy| Stack: Last-in-first-out Data Structure

|200|[Number of Islands](https://leetcode.com/problems/number-of-islands/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_200.java) & Python|Medium| Queue and BFS

|225|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_225.java) & Python|Easy| Conclusion

|232|[Implement Queue using Stacks](https://leetcode.com/problems/implement-queue-using-stacks/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_232.java) & Python|Easy| Conclusion

|279|[Perfect Squares](https://leetcode.com/problems/perfect-squares/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_279.java) & Python|Medium| Queue and BFS

|394|[Decode String](https://leetcode.com/problems/decode-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_394.java) & Python|Medium| Conclusion

|494|[Target Sum](https://leetcode.com/problems/target-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_494.java) & Python|Medium| Stack and DFS

|542|[01 Matrix](https://leetcode.com/problems/01-matrix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_542.java) & Python|Medium| Conclusion

|622|[Design Circular Queue](https://leetcode.com/problems/longest-common-prefix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_622.java) & Python|Medium| Queue: First-in-first-out Data Structure

|733|[Flood Fill](https://leetcode.com/problems/flood-fill/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_733.java) & Python|Easy| Conclusion

|739|[Daily Temperatures](https://leetcode.com/problems/daily-temperatures/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_739.java) & Python|Medium| Stack: Last-in-first-out Data Structure

|752|[Open the Lock](https://leetcode.com/problems/open-the-lock/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_752.java) & Python|Medium| Queue and BFS

|841|[Keys and Rooms](https://leetcode.com/problems/keys-and-rooms/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_841.java) & Python|Medium| Conclusion

### Linked List

|  #  |      Title     |   Solutions  |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_2.java) & Python|Medium| Conclusion

|19|[Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_19.java) & Python|Medium| Two Pointer Technique

|21|[Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_21.java) & Python|Easy| Conclusion

|61|[Rotate List](https://leetcode.com/problems/rotate-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_61.java) & Python|Medium| Conclusion

|135|[Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_135.java) & Python|Medium| Conclusion

|141|[Linked List Cycle](https://leetcode.com/problems/number-of-islands/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_141.java) & Python|Easy| Two Pointer Technique

|142|[Linked List Cycle II](https://leetcode.com/problems/linked-list-cycle-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_142.java) & Python|Medium| Two Pointer Technique

|160|[Intersection of Two Linked Lists](https://leetcode.com/problems/intersection-of-two-linked-lists/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_160.java) & Python|Easy| Two Pointer Technique

|203|[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_203.java) & Python|Easy| Classic Problems

|206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_206.java) & Python|Easy| Classic Problems

|234|[Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_234.java) & Python|Easy| Classic Problems

|328|[Odd Even Linked List](https://leetcode.com/problems/odd-even-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_328.java) & Python|Medium| Classic Problems

|430|[Flatten a Multilevel Doubly Linked List](https://leetcode.com/problems/flatten-a-multilevel-doubly-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_430.java) & Python|Medium| Conclusion

|707|[Design Linked List](https://leetcode.com/problems/number-of-islands/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_707.java) & Python|Easy| Singly Linked List

### Hash Table

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|1|[Two Sum](https://leetcode.com/problems/two-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_1.java) & Python |Easy| Practical Application - Hash Map

|3|[Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_3.java) & Python |Medium| Conclusion

|36|[Valid Sudoku](https://leetcode.com/problems/valid-sudoku/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_36.java) & Python |Medium| Practical Application - Design the Key

|49|[Group Anagrams](https://leetcode.com/problems/group-anagrams/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_49.java) & Python |Medium| Practical Application - Design the Key

|136|[Single Number](https://leetcode.com/problems/single-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_136.java) & Python |Easy| Practical Application - Hash Set

|202|[Happy Number](https://leetcode.com/problems/happy-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_202.java) & Python |Easy| Practical Application - Hash Set

|205|[Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_205.java) & Python |Easy| Practical Application - Hash Map

|217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_217.java) & Python |Easy| Practical Application - Hash Set

|219|[Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_219.java) & Python |Easy| Practical Application - Hash Map

|347|[Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_347.java) & Python |Medium| Conclusion

|349|[Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_349.java) & Python |Easy| Practical Application - Hash Set

|350|[Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_350.java) & Python |Easy| Practical Application - Hash Map

|380|[Insert Delete GetRandom O(1)](https://leetcode.com/problems/insert-delete-getrandom-o1/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_380.java) & Python |Medium| Conclusion

|387|[First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_387.java) & Python |Easy| Practical Application - Hash Map

|454|[4Sum II](https://leetcode.com/problems/4sum-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_454.java) & Python |Medium| Conclusion

|599|[Minimum Index Sum of Two Lists](https://leetcode.com/problems/minimum-index-sum-of-two-lists/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_599.java) & Python |Easy| Practical Application - Hash Map

|652|[Find Duplicate Subtrees](https://leetcode.com/problems/find-duplicate-subtrees/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_652.java) & Python |Medium| Practical Application - Design the Key

|705|[Design HashSet](https://leetcode.com/problems/design-hashset/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_705.java) & Python |Easy| Design a Hash Table

|706|[Design HashMap](https://leetcode.com/problems/design-hashmap/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_706.java) & Python |Easy| Design a Hash Table

|771|[Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_771.java) & Python |Easy| Conclusion

### Binary Search

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|4|[Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_4.java) & Python |Hard| More Practices II

|33|[Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_33.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_33.py)|Medium| Template I

|34|[Find First and Last Position of Element in Sorted Array](https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_34.java) & Python |Medium| Template III

|50|[Pow(x, n)](https://leetcode.com/problems/powx-n/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_50.java) & Python |Medium| Conclusion

|69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_69.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_69.py)|Easy| Template I

|153|[Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_153.java) & Python|Medium| Template II

|154|[Find Minimum in Rotated Sorted Array II](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_154.java) & Python| Hard| More Practices

|162|[Find Peak Element](https://leetcode.com/problems/find-peak-element/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_162.java) & Python|Medium| Template II

|167|[Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_167.java) & Python |Easy| More Practices

|278|[First Bad Version](https://leetcode.com/problems/first-bad-version/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_278.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_278.py)|Easy| Template II

|287|[Find the Duplicate Number](https://leetcode.com/problems/find-the-duplicate-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_287.java) & Python |Medium| More Practices II

|349|[Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_349.java) & Python |Easy| More Practices

|350|[Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_350.java) & Python |Easy| More Practices

|367|[Valid Perfect Square](https://leetcode.com/problems/valid-perfect-square/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_367.java) & Python |Easy| Conclusion

|374|[Guess Number Higher or Lower](https://leetcode.com/problems/guess-number-higher-or-lower/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_374.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_374.py)|Easy| Template I

|410|[Split Array Largest Sum](https://leetcode.com/problems/split-array-largest-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_410.java) & Python |Hard| More Practices II

|658|[Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_658.java) & Python |Medium| Template III

|704|[Binary Search](https://leetcode.com/problems/binary-search/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_704.java) & [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_704.py)|Easy| Background

|719|[Find K-th Smallest Pair Distance](https://leetcode.com/problems/find-k-th-smallest-pair-distance/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_719.java) & Python |Hard| More Practices II

|744|[Find Smallest Letter Greater Than Target](https://leetcode.com/problems/find-smallest-letter-greater-than-target/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_744.java) & Python|Easy| Conclusion

### Binary Tree

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|94|[Binary Tree Inorder Traversal](https://leetcode.com/problems/binary-tree-inorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_94.java) & Python |Medium| Traverse A Tree

|101|[Symmetric Tree](https://leetcode.com/problems/symmetric-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_101.java) & Python |Easy| Solve Tree Problems Recursively

|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_102.java) & Python |Medium| Traverse A Tree

|104|[Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_104.java) & Python |Easy| Solve Tree Problems Recursively

|105|[Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_105.java) & Python |Medium| Conclusion

|106|[Construct Binary Tree from Inorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_106.java) & Python |Medium| Conclusion

|112|[Path Sum](https://leetcode.com/problems/path-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_112.java) & Python |Easy| Solve Tree Problems Recursively

|116|[Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_116.java) & Python |Medium| Conclusion

|117|[Populating Next Right Pointers in Each Node II](https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_117.java) & Python |Medium| Conclusion

|144|[Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_144.java) & Python |Medium| Traverse A Tree

|145|[Binary Tree Postorder Traversal](https://leetcode.com/problems/binary-tree-postorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_145.java) & Python |Hard| Traverse A Tree

|236|[Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_236.java) & Python |Medium| Conclusion

|297|[Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_297.java) & Python |Medium| Conclusion

### Binary Search Tree

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|98|[Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_98.java) & Python |Medium| Introduction to BST

|108|[Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_108.java) & Python |Easy| Appendix: Height-balanced BST

|110|[Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_110.java) & Python |Easy| Appendix: Height-balanced BST

|173|[Binary Search Tree Iterator](https://leetcode.com/problems/binary-search-tree-iterator/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_173.java) & Python |Medium| Introduction to BST

|220|[Contains Duplicate III](https://leetcode.com/problems/contains-duplicate-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_220.java) & Python |Medium| Conclusion

|235|[Lowest Common Ancestor of a Binary Search Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_235.java) & Python |Easy| Conclusion

|450|[Delete Node in a BST](https://leetcode.com/problems/delete-node-in-a-bst/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_450.java) & Python |Medium| Basic Operations in BST

|700|[Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_700.java) & Python |Easy| Basic Operations in BST

|701|[Insert into a Binary Search Tree](https://leetcode.com/problems/insert-into-a-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_701.java) & Python |Medium| Basic Operations in BST

|703|[Kth Largest Element in a Stream](https://leetcode.com/problems/kth-largest-element-in-a-stream/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_703.java) & Python |Easy| Conclusion

### N-ary Tree

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|429|[N-ary Tree Level Order Traversal](https://leetcode.com/problems/n-ary-tree-level-order-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/n_ary_tree/_429.java) & Python |Easy| Traversal

|559|[Maximum Depth of N-ary Tree](https://leetcode.com/problems/maximum-depth-of-n-ary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/n_ary_tree/_559.java) & Python |Easy| Recursion

|589|[N-ary Tree Preorder Traversal](https://leetcode.com/problems/n-ary-tree-preorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/n_ary_tree/_589.java) & Python |Easy| Traversal

|590|[N-ary Tree Postorder Traversal](https://leetcode.com/problems/n-ary-tree-postorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/n_ary_tree/_590.java) & Python |Easy| Traversal

### Trie (Prefix Tree)

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|208|[Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_208.java) & Python |Medium| Basic Operations

|211|[Add and Search Word - Data structure design](https://leetcode.com/problems/add-and-search-word-data-structure-design/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_211.java) & Python |Medium| Practical Application I

|212|[Word Search II](https://leetcode.com/problems/word-search-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_212.java) & Python |Hard| Practical Application II

|336|[Palindrome Pairs](https://leetcode.com/problems/palindrome-pairs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_336.java) & Python |Hard| Practical Application II

|421|[Maximum XOR of Two Numbers in an Array](https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_421.java) & Python |Medium| Practical Application II

|648|[Replace Words](https://leetcode.com/problems/replace-words/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_648.java) & Python |Medium| Practical Application I

|677|[Map Sum Pairs](https://leetcode.com/problems/map-sum-pairs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_677.java) & Python |Medium| Practical Application I

### Decision Tree

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

| ### |[Calculate Entropy](https://leetcode.com/explore/learn/card/decision-tree/285/implementation/2650/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/decision_tree/CalculateEntropy.java) & Python |Easy| Implementation

| ### |[Calculate Maximum Information Gain](https://leetcode.com/explore/learn/card/decision-tree/285/implementation/2651/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/decision_tree/CalculateMaxInfoGain.java) & Python |Easy| Implementation

### Recursion I

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|21|[Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_21.java) & Python|Easy| Conclusion

|24|[Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_i/_24.java) & Python| Medium| Principle of Recursion

|50|[Pow(x, n)](https://leetcode.com/problems/powx-n/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_50.java) & Python |Medium| Complexity Analysis

|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_70.java) & Python| Easy| Memoization

|95|[Unique Binary Search Trees II](https://leetcode.com/problems/unique-binary-search-trees-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_95.java) & Python|Medium| Conclusion

|104|[Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_104.java) & Python |Easy| Complexity Analysis

|118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_118.java) & Python| Easy| Recurrence Relation

|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_119.java) & Python| Easy| Recurrence Relation

|206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_206.java) & Python|Easy| Recurrence Relation

|344|[Reverse String](https://leetcode.com/problems/reverse-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_344.java) & Python| Easy| Principle of Recursion

|509|[Fibonacci Number](https://leetcode.com/problems/fibonacci-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_509.java) & Python| Easy| Memoization

|779|[K-th Symbol in Grammar](https://leetcode.com/problems/k-th-symbol-in-grammar/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_779.java) & Python|Medium| Conclusion

### Recursion II

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|17|[Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_17.java) & Python |Medium| Conclusion

|22|[Generate Parentheses](https://leetcode.com/problems/generate-parentheses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_22.java) & Python |Medium| Recursion to Iteration

|37|[Sudoku Solver](https://leetcode.com/problems/sudoku-solver/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_37.java) & Python |Hard| Backtracking

|46|[Permutations](https://leetcode.com/problems/permutations/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_46.java) & Python |Medium| Conclusion

|52|[N-Queens II](https://leetcode.com/problems/n-queens-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_52.java) & Python |Hard| Backtracking

|77|[Combinations](https://leetcode.com/problems/combinations/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_77.java) & Python |Medium| Backtracking

|84|[Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_84.java) & Python |Hard| Conclusion

|94|[Binary Tree Inorder Traversal](https://leetcode.com/problems/binary-tree-inorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_94.java) & Python |Medium| Recursion to Iteration

|98|[Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_98.java) & Python |Medium| Divide and Conquer

|100|[Same Tree](https://leetcode.com/problems/same-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_100.java) & Python |Easy| Recursion to Iteration

|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_102.java) & Python |Medium| Recursion to Iteration

|218|[The Skyline Problem](https://leetcode.com/problems/the-skyline-problem/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_218.java) & Python |Hard| Conclusion

|240|[Search a 2D Matrix II](https://leetcode.com/problems/search-a-2d-matrix-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_240.java) & Python |Medium| Divide and Conquer

|912|[Sort an Array](https://leetcode.com/problems/sort-an-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_912.java) & Python|Medium| Divide and Conquer

### Concurrency

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|1114|[Print in Order](https://leetcode.com/problems/print-in-order/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1114.java) & Python |Easy| Concurrency

|1115|[Print FooBar Alternately](https://leetcode.com/problems/print-foobar-alternately/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1115.java) & Python |Medium| Concurrency

|1116|[Print Zero Even Odd](https://leetcode.com/problems/print-zero-even-odd/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1116.java) & Python |Medium| Concurrency

|1117|[Building H2O](https://leetcode.com/problems/building-h2o/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1117.java) & Python |Medium| Concurrency

|1195|[Fizz Buzz Multithreaded](https://leetcode.com/problems/fizz-buzz-multithreaded/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1195.java) & Python |Medium| Concurrency

|1226|[The Dining Philosophers](https://leetcode.com/problems/the-dining-philosophers/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1226.java) & Python |Medium| Concurrency

### Others

|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   

|-----|----------------|:---------------:|:--------:|:-------------:

|6|[ZigZag Conversion](https://leetcode.com/problems/zigzag-conversion/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_6.java) & Python |Medium| Others

|9|[Palindrome Number](https://leetcode.com/problems/palindrome-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_9.java) & Python |Easy| Others

|12|[Integer to Roman](https://leetcode.com/problems/integer-to-roman/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_12.java) & Python |Medium| Others

|16|[3Sum Closest](https://leetcode.com/problems/3sum-closest/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_16.java) & Python |Medium| Others

|18|[4Sum](https://leetcode.com/problems/4sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_18.java) & Python |Medium| Others

|25|[Reverse Nodes in k-Group](https://leetcode.com/problems/reverse-nodes-in-k-group/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_25.java) & Python |Hard| Others

|30|[Substring with Concatenation of All Words](https://leetcode.com/problems/substring-with-concatenation-of-all-words/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_30.java) & Python |Hard| Others

|31|[Next Permutation](https://leetcode.com/problems/next-permutation/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_31.java) & Python |Medium| Others

|32|[Longest Valid Parentheses](https://leetcode.com/problems/longest-valid-parentheses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_32.java) & Python |Hard| Others

|35|[Search Insert Position](https://leetcode.com/problems/search-insert-position/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_35.java) & Python |Easy| Others

|39|[Combination Sum](https://leetcode.com/problems/combination-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_39.java) & Python |Medium| Others

|40|[Combination Sum II](https://leetcode.com/problems/combination-sum-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_40.java) & Python |Medium| Others

|43|[Multiply Strings](https://leetcode.com/problems/multiply-strings/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_43.java) & Python |Medium| Others

|45|[Jump Game II](https://leetcode.com/problems/jump-game-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_45.java) & Python |Hard| Others

|47|[Permutations II](https://leetcode.com/problems/permutations-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_47.java) & Python |Medium| Others

|51|[N-Queens](https://leetcode.com/problems/n-queens/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_51.java) & Python |Hard| Others

|57|[Insert Interval](https://leetcode.com/problems/insert-interval/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_57.java) & Python |Hard| Others

|58|[Length of Last Word](https://leetcode.com/problems/length-of-last-word/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_58.java) & Python |Easy| Others

|59|[Spiral Matrix II](https://leetcode.com/problems/spiral-matrix-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_59.java) & Python |Medium| Others

|60|[Permutation Sequence](https://leetcode.com/problems/permutation-sequence/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_60.java) & Python |Medium| Others

|63|[Unique Paths II](https://leetcode.com/problems/unique-paths-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_63.java) & Python |Medium| Others

|64|[Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_64.java) & Python |Medium| Others

|65|[Valid Number](https://leetcode.com/problems/valid-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_65.java) & Python |Hard| Others

|68|[Text Justification](https://leetcode.com/problems/text-justification/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_68.java) & Python |Hard| Others

|71|[Simplify Path](https://leetcode.com/problems/simplify-path/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_71.java) & Python |Medium| Others

|72|[Edit Distance](https://leetcode.com/problems/edit-distance/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_72.java) & Python |Hard| Others

|74|[Search a 2D Matrix](https://leetcode.com/problems/search-a-2d-matrix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_74.java) & Python |Medium| Others

|80|[Remove Duplicates from Sorted Array II](https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_80.java) & Python |Medium| Others

|81|[Search in Rotated Sorted Array II](https://leetcode.com/problems/search-in-rotated-sorted-array-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_81.java) & Python |Medium| Others

|82|[Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_82.java) & Python |Medium| Others

|83|[Remove Duplicates from Sorted List](https://leetcode.com/problems/remove-duplicates-from-sorted-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_83.java) & Python |Easy| Others

|85|[Maximal Rectangle](https://leetcode.com/problems/maximal-rectangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_85.java) & Python |Hard| Others

|86|[Partition List](https://leetcode.com/problems/partition-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_86.java) & Python |Medium| Others

|87|[Scramble String](https://leetcode.com/problems/scramble-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_87.java) & Python |Hard| Others

|89|[Gray Code](https://leetcode.com/problems/gray-code/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_89.java) & Python |Medium| Others

|90|[Subsets II](https://leetcode.com/problems/subsets-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_90.java) & Python |Medium| Others

|92|[Reverse Linked List II](https://leetcode.com/problems/reverse-linked-list-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_92.java) & Python |Medium| Others

|93|[Restore IP Addresses](https://leetcode.com/problems/restore-ip-addresses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_93.java) & Python |Medium| Others

|96|[Unique Binary Search Trees](https://leetcode.com/problems/unique-binary-search-trees/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_96.java) & Python |Medium| Others

|97|[Interleaving String](https://leetcode.com/problems/interleaving-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_97.java) & Python |Hard| Others

|99|[Recover Binary Search Tree](https://leetcode.com/problems/recover-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_99.java) & Python |Hard| Others

|107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_107.java) & Python |Easy| Others

|109|[Convert Sorted List to Binary Search Tree](https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_109.java) & Python |Medium| Others

|111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_111.java) & Python |Easy| Others

|113|[Path Sum II](https://leetcode.com/problems/path-sum-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_113.java) & Python |Medium| Others

|114|[Flatten Binary Tree to Linked List](https://leetcode.com/problems/flatten-binary-tree-to-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_114.java) & Python |Medium| Others

|115|[Distinct Subsequences](https://leetcode.com/problems/distinct-subsequences/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_115.java) & Python |Hard| Others

|120|[Triangle](https://leetcode.com/problems/triangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_120.java) & Python |Medium| Others

|123|[Best Time to Buy and Sell Stock III](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_123.java) & Python |Hard| Others

|126|[Word Ladder II](https://leetcode.com/problems/word-ladder-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_126.java) & Python |Hard| Others

|129|[Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_129.java) & Python |Medium| Others

|132|[Palindrome Partitioning II](https://leetcode.com/problems/palindrome-partitioning-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_132.java) & Python |Hard| Others

|134|[Gas Station](https://leetcode.com/problems/gas-station/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_134.java) & Python |Medium| Others

|135|[Candy](https://leetcode.com/problems/candy/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_135.java) & Python |Hard| Others

|137|[Single Number II](https://leetcode.com/problems/single-number-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_137.java) & Python |Medium| Others

|143|[Reorder List](https://leetcode.com/problems/reorder-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_143.java) & Python |Medium| Others

|147|[Insertion Sort List](https://leetcode.com/problems/insertion-sort-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_147.java) & Python |Medium| Others

|164|[Maximum Gap](https://leetcode.com/problems/maximum-gap/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_164.java) & Python |Hard| Others

|165|[Compare Version Numbers](https://leetcode.com/problems/compare-version-numbers/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_165.java) & Python |Medium| Others

|168|[Excel Sheet Column Title](https://leetcode.com/problems/excel-sheet-column-title/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_168.java) & Python |Easy| Others

|174|[Dungeon Game](https://leetcode.com/problems/dungeon-game/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_174.java) & Python |Hard| Others

|187|[Repeated DNA Sequences](https://leetcode.com/problems/repeated-dna-sequences/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_187.java) & Python |Medium| Others

|188|[Best Time to Buy and Sell Stock IV](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iv/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_188.java) & Python |Hard| Others

|199|[Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_199.java) & Python |Medium| Others

|201|[Bitwise AND of Numbers Range](https://leetcode.com/problems/bitwise-and-of-numbers-range/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_201.java) & Python |Medium| Others

|213|[House Robber II](https://leetcode.com/problems/house-robber-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_213.java) & Python |Medium| Others

|214|[Shortest Palindrome](https://leetcode.com/problems/shortest-palindrome/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_214.java) & Python |Hard| Others

|216|[Combination Sum III](https://leetcode.com/problems/combination-sum-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_216.java) & Python |Medium| Others

|221|[Maximal Square](https://leetcode.com/problems/maximal-square/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_221.java) & Python |Medium| Others

|222|[Count Complete Tree Nodes](https://leetcode.com/problems/count-complete-tree-nodes/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_222.java) & Python |Medium| Others

|223|[Rectangle Area](https://leetcode.com/problems/rectangle-area/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_223.java) & Python |Medium| Others

|224|[Basic Calculator](https://leetcode.com/problems/basic-calculator/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_224.java) & Python |Hard| Others

|226|[Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_226.java) & Python |Easy| Others

|228|[Summary Ranges](https://leetcode.com/problems/summary-ranges/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_228.java) & Python |Medium| Others

|229|[Majority Element II](https://leetcode.com/problems/majority-element-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_229.java) & Python |Medium| Others

|231|[Power of Two](https://leetcode.com/problems/power-of-two/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_231.java) & Python |Easy| Others

|233|[Number of Digit One](https://leetcode.com/problems/number-of-digit-one/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_233.java) & Python |Hard| Others

|241|[Different Ways to Add Parentheses](https://leetcode.com/problems/different-ways-to-add-parentheses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_241.java) & Python |Medium| Others

|257|[Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_257.java) & Python |Easy| Others

|258|[Add Digits](https://leetcode.com/problems/add-digits/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_258.java) & Python |Easy| Others

|260|[Single Number III](https://leetcode.com/problems/single-number-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_260.java) & Python |Medium| Others

|263|[Ugly Number](https://leetcode.com/problems/ugly-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_263.java) & Python |Easy| Others

|264|[Ugly Number II](https://leetcode.com/problems/ugly-number-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_264.java) & Python |Medium| Others

|273|[Integer to English Words](https://leetcode.com/problems/integer-to-english-words/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_273.java) & Python |Hard| Others

|274|[H-Index](https://leetcode.com/problems/h-index/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_274.java) & Python |Medium| Others

|275|[H-Index II](https://leetcode.com/problems/h-index-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_275.java) & Python |Medium| Others

|282|[Expression Add Operators](https://leetcode.com/problems/expression-add-operators/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_282.java) & Python |Hard| Others

|284|[Peeking Iterator](https://leetcode.com/problems/peeking-iterator/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_284.java) & Python |Medium| Others

|290|[Word Pattern](https://leetcode.com/problems/word-pattern/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_290.java) & Python |Easy| Others

|292|[Nim Game](https://leetcode.com/problems/nim-game/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_292.java) & Python |Easy| Others

|299|[Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_299.java) & Python |Easy| Others

|303|[Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_303.java) & Python |Easy| Others

|304|[Range Sum Query 2D - Immutable](https://leetcode.com/problems/range-sum-query-2d-immutable/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_304.java) & Python |Medium| Others

|306|[Additive Number](https://leetcode.com/problems/additive-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_306.java) & Python |Medium| Others

|307|[Range Sum Query - Mutable](https://leetcode.com/problems/range-sum-query-mutable/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_307.java) & Python |Medium| Others

|310|[Minimum Height Trees](https://leetcode.com/problems/minimum-height-trees/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_310.java) & Python |Medium| Others

|313|[Super Ugly Number](https://leetcode.com/problems/super-ugly-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_313.java) & Python |Medium| Others

|316|[Remove Duplicate Letters](https://leetcode.com/problems/remove-duplicate-letters/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_316.java) & Python |Hard| Others

|318|[Maximum Product of Word Lengths](https://leetcode.com/problems/maximum-product-of-word-lengths/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_318.java) & Python |Medium| Others

|319|[Bulb Switcher](https://leetcode.com/problems/bulb-switcher/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_319.java) & Python |Medium| Others

|321|[Create Maximum Number](https://leetcode.com/problems/create-maximum-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_321.java) & Python |Hard| Others

|327|[Count of Range Sum](https://leetcode.com/problems/count-of-range-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_327.java) & Python |Hard| Others

|330|[Patching Array](https://leetcode.com/problems/patching-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_330.java) & Python |Hard| Others

|331|[Verify Preorder Serialization of a Binary Tree](https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_331.java) & Python |Medium| Others

|332|[Reconstruct Itinerary](https://leetcode.com/problems/reconstruct-itinerary/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_332.java) & Python |Medium| Others

|335|[Self Crossing](https://leetcode.com/problems/self-crossing/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_335.java) & Python |Hard| Others

|337|[House Robber III](https://leetcode.com/problems/house-robber-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_337.java) & Python |Medium| Others

|338|[Counting Bits](https://leetcode.com/problems/counting-bits/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_338.java) & Python |Medium| Others

|342|[Power of Four](https://leetcode.com/problems/power-of-four/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_342.java) & Python |Easy| Others

|343|[Integer Break](https://leetcode.com/problems/integer-break/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_343.java) & Python |Medium| Others

|345|[Reverse Vowels of a String](https://leetcode.com/problems/reverse-vowels-of-a-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_345.java) & Python |Easy| Others

|352|[Data Stream as Disjoint Intervals](https://leetcode.com/problems/data-stream-as-disjoint-intervals/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_352.java) & Python |Hard| Others

|354|[Russian Doll Envelopes](https://leetcode.com/problems/russian-doll-envelopes/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_354.java) & Python |Hard| Others

|355|[Design Twitter](https://leetcode.com/problems/design-twitter/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_355.java) & Python |Medium| Others

|357|[Count Numbers with Unique Digits](https://leetcode.com/problems/count-numbers-with-unique-digits/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_357.java) & Python |Medium| Others

|363|[Max Sum of Rectangle No Larger Than K](https://leetcode.com/problems/max-sum-of-rectangle-no-larger-than-k/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_363.java) & Python |Hard| Others

|365|[Water and Jug Problem](https://leetcode.com/problems/water-and-jug-problem/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_365.java) & Python |Medium| Others

|368|[Largest Divisible Subset](https://leetcode.com/problems/largest-divisible-subset/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_368.java) & Python |Medium| Others

|372|[Super Pow](https://leetcode.com/problems/super-pow/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_372.java) & Python |Medium| Others

|373|[Find K Pairs with Smallest Sums](https://leetcode.com/problems/find-k-pairs-with-smallest-sums/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_373.java) & Python |Medium| Others

|375|[Guess Number Higher or Lower II](https://leetcode.com/problems/guess-number-higher-or-lower-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_375.java) & Python |Medium| Others

|376|[Wiggle Subsequence](https://leetcode.com/problems/wiggle-subsequence/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_376.java) & Python |Medium| Others

|377|[Combination Sum IV](https://leetcode.com/problems/combination-sum-iv/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_377.java) & Python |Medium| Others

|381|[Insert Delete GetRandom O(1) - Duplicates allowed](https://leetcode.com/problems/insert-delete-getrandom-o1-duplicates-allowed/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_381.java) & Python |Hard| Others

|382|[Linked List Random Node](https://leetcode.com/problems/linked-list-random-node/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_382.java) & Python |Medium| Others

|383|[Ransom Note](https://leetcode.com/problems/ransom-note/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_383.java) & Python |Easy| Others

|385|[Mini Parser](https://leetcode.com/problems/mini-parser/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_385.java) & Python |Medium| Others

|386|[Lexicographical Numbers](https://leetcode.com/problems/lexicographical-numbers/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_386.java) & Python |Medium| Others

|388|[Longest Absolute File Path](https://leetcode.com/problems/longest-absolute-file-path/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_388.java) & Python |Medium| Others

|389|[Find the Difference](https://leetcode.com/problems/find-the-difference/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_389.java) & Python |Easy| Others

|390|[Elimination Game](https://leetcode.com/problems/elimination-game/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_390.java) & Python |Medium| Others

|391|[Perfect Rectangle](https://leetcode.com/problems/perfect-rectangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_391.java) & Python |Hard| Others

|392|[Is Subsequence](https://leetcode.com/problems/is-subsequence/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_392.java) & Python |Easy| Others

|393|[UTF-8 Validation](https://leetcode.com/problems/utf-8-validation/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_393.java) & Python |Medium| Others

|395|[Longest Substring with At Least K Repeating Characters](https://leetcode.com/problems/longest-substring-with-at-least-k-repeating-characters/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_395.java) & Python |Medium| Others

|396|[Rotate Function](https://leetcode.com/problems/rotate-function/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_396.java) & Python |Medium| Others

|397|[Integer Replacement](https://leetcode.com/problems/integer-replacement/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_397.java) & Python |Medium| Others

|398|[Random Pick Index](https://leetcode.com/problems/random-pick-index/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_398.java) & Python |Medium| Others

|399|[Evaluate Division](https://leetcode.com/problems/evaluate-division/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_399.java) & Python |Medium| Others

|400|[Nth Digit](https://leetcode.com/problems/nth-digit/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_400.java) & Python |Medium| Others

|401|[Binary Watch](https://leetcode.com/problems/binary-watch/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_401.java) & Python |Easy| Others

|402|[Remove K Digits](https://leetcode.com/problems/remove-k-digits/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_402.java) & Python |Medium| Others

|403|[Frog Jump](https://leetcode.com/problems/frog-jump/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_403.java) & Python |Hard| Others

|404|[Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_404.java) & Python |Easy| Others

|405|[Convert a Number to Hexadecimal](https://leetcode.com/problems/convert-a-number-to-hexadecimal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_405.java) & Python |Easy| Others

|407|[Trapping Rain Water II](https://leetcode.com/problems/trapping-rain-water-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_407.java) & Python |Hard| Others

|409|[Longest Palindrome](https://leetcode.com/problems/longest-palindrome/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_409.java) & Python |Easy| Others

|413|[Arithmetic Slices](https://leetcode.com/problems/arithmetic-slices/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_413.java) & Python |Medium| Others

|414|[Third Maximum Number](https://leetcode.com/problems/third-maximum-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_414.java) & Python |Easy| Others

|415|[Add Strings](https://leetcode.com/problems/add-strings/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_415.java) & Python |Easy| Others

|416|[Partition Equal Subset Sum](https://leetcode.com/problems/partition-equal-subset-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_416.java) & Python |Medium| Others

|417|[Pacific Atlantic Water Flow](https://leetcode.com/problems/pacific-atlantic-water-flow/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_417.java) & Python |Medium| Others

|419|[Battleships in a Board](https://leetcode.com/problems/battleships-in-a-board/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_419.java) & Python |Medium| Others

|420|[Strong Password Checker](https://leetcode.com/problems/strong-password-checker/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_420.java) & Python |Hard| Others

|423|[Reconstruct Original Digits from English](https://leetcode.com/problems/reconstruct-original-digits-from-english/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_423.java) & Python |Medium| Others

|424|[Longest Repeating Character Replacement](https://leetcode.com/problems/longest-repeating-character-replacement/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_424.java) & Python |Medium| Others

|427|[Construct Quad Tree](https://leetcode.com/problems/construct-quad-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_427.java) & Python |Medium| Others

|432|[All O\`one Data Structure](https://leetcode.com/problems/all-oone-data-structure/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_432.java) & Python |Hard| Others

|433|[Minimum Genetic Mutation](https://leetcode.com/problems/minimum-genetic-mutation/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_433.java) & Python |Medium| Others

|434|[Number of Segments in a String](https://leetcode.com/problems/number-of-segments-in-a-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_434.java) & Python |Easy| Others

|435|[Non-overlapping Intervals](https://leetcode.com/problems/non-overlapping-intervals/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_435.java) & Python |Medium| Others

|436|[Find Right Interval](https://leetcode.com/problems/find-right-interval/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_436.java) & Python |Medium| Others

|437|[Path Sum III](https://leetcode.com/problems/path-sum-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_437.java) & Python |Easy| Others

|438|[Find All Anagrams in a String](https://leetcode.com/problems/find-all-anagrams-in-a-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_438.java) & Python |Medium| Others

|440|[K-th Smallest in Lexicographical Order](https://leetcode.com/problems/k-th-smallest-in-lexicographical-order/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_440.java) & Python |Hard| Others

|441|[Arranging Coins](https://leetcode.com/problems/arranging-coins/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_441.java) & Python |Easy| Others

|442|[Find All Duplicates in an Array](https://leetcode.com/problems/find-all-duplicates-in-an-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_442.java) & Python |Medium| Others

|443|[String Compression](https://leetcode.com/problems/string-compression/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_443.java) & Python |Easy| Others

|445|[Add Two Numbers II](https://leetcode.com/problems/add-two-numbers-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_445.java) & Python |Medium| Others

|446|[Arithmetic Slices II - Subsequence](https://leetcode.com/problems/arithmetic-slices-ii-subsequence/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_446.java) & Python |Hard| Others

|447|[Number of Boomerangs](https://leetcode.com/problems/number-of-boomerangs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_447.java) & Python |Easy| Others

|448|[Find All Numbers Disappeared in an Array](https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_448.java) & Python |Easy| Others

|449|[Serialize and Deserialize BST](https://leetcode.com/problems/serialize-and-deserialize-bst/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_449.java) & Python |Medium| Others

|451|[Sort Characters By Frequency](https://leetcode.com/problems/sort-characters-by-frequency/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_451.java) & Python |Medium| Others

|452|[Minimum Number of Arrows to Burst Balloons](https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_452.java) & Python |Medium| Others

|453|[Minimum Moves to Equal Array Elements](https://leetcode.com/problems/minimum-moves-to-equal-array-elements/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_453.java) & Python |Easy| Others

|455|[Assign Cookies](https://leetcode.com/problems/assign-cookies/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_455.java) & Python |Easy| Others

|456|[132 Pattern](https://leetcode.com/problems/132-pattern/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_456.java) & Python |Medium| Others

|457|[Circular Array Loop](https://leetcode.com/problems/circular-array-loop/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_457.java) & Python |Medium| Others

|458|[Poor Pigs](https://leetcode.com/problems/poor-pigs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_458.java) & Python |Hard| Others

|459|[Repeated Substring Pattern](https://leetcode.com/problems/repeated-substring-pattern/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_459.java) & Python |Easy| Others

|460|[LFU Cache](https://leetcode.com/problems/lfu-cache/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_460.java) & Python |Hard| Others

|462|[Minimum Moves to Equal Array Elements II](https://leetcode.com/problems/minimum-moves-to-equal-array-elements-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_462.java) & Python |Medium| Others

|463|[Island Perimeter](https://leetcode.com/problems/island-perimeter/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_463.java) & Python |Easy| Others

|464|[Can I Win](https://leetcode.com/problems/can-i-win/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_464.java) & Python |Medium| Others

|466|[Count The Repetitions](https://leetcode.com/problems/count-the-repetitions/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_466.java) & Python |Hard| Others

|467|[Unique Substrings in Wraparound String](https://leetcode.com/problems/unique-substrings-in-wraparound-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_467.java) & Python |Medium| Others

|468|[Validate IP Address](https://leetcode.com/problems/validate-ip-address/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_468.java) & Python |Medium| Others

|470|[Implement Rand10() Using Rand7()](https://leetcode.com/problems/implement-rand10-using-rand7/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_470.java) & Python |Medium| Others

|472|[Concatenated Words](https://leetcode.com/problems/concatenated-words/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_472.java) & Python |Hard| Others

|473|[Matchsticks to Square](https://leetcode.com/problems/matchsticks-to-square/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_473.java) & Python |Medium| Others

|474|[Ones and Zeroes](https://leetcode.com/problems/ones-and-zeroes/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_474.java) & Python |Medium| Others

|475|[Heaters](https://leetcode.com/problems/heaters/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_475.java) & Python |Easy| Others

|476|[Number Complement](https://leetcode.com/problems/number-complement/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_476.java) & Python |Easy| Others

|477|[Total Hamming Distance](https://leetcode.com/problems/total-hamming-distance/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_477.java) & Python |Medium| Others

|478|[Generate Random Point in a Circle](https://leetcode.com/problems/generate-random-point-in-a-circle/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_478.java) & Python |Medium| Others

|479|[Largest Palindrome Product](https://leetcode.com/problems/largest-palindrome-product/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_479.java) & Python |Hard| Others

|480|[Sliding Window Median](https://leetcode.com/problems/sliding-window-median/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_480.java) & Python |Hard| Others

|481|[Magical String](https://leetcode.com/problems/magical-string/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_481.java) & Python |Medium| Others

|482|[License Key Formatting](https://leetcode.com/problems/license-key-formatting/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_482.java) & Python |Easy| Others

|483|[Smallest Good Base](https://leetcode.com/problems/smallest-good-base/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_483.java) & Python |Hard| Others

|486|[Predict the Winner](https://leetcode.com/problems/predict-the-winner/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_486.java) & Python |Medium| Others

|488|[Zuma Game](https://leetcode.com/problems/zuma-game/)|[Java](https://github.com/guobinh