https://github.com/himudigonda/leetcode
My LeetCode Journey
https://github.com/himudigonda/leetcode
algorithms-and-data-structures data-structures-and-algorithms dsa dsa-practice python sql
Last synced: 6 months ago
JSON representation
My LeetCode Journey
- Host: GitHub
- URL: https://github.com/himudigonda/leetcode
- Owner: himudigonda
- Created: 2025-02-08T13:27:05.000Z (11 months ago)
- Default Branch: main
- Last Pushed: 2025-06-30T06:38:06.000Z (7 months ago)
- Last Synced: 2025-06-30T06:39:34.776Z (7 months ago)
- Topics: algorithms-and-data-structures, data-structures-and-algorithms, dsa, dsa-practice, python, sql
- Language: Python
- Homepage:
- Size: 106 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# LeetCode Solutions Overview
## 🧮 Summary Stats
**Total Problems Solved:** 53
**By Difficulty:**
| Difficulty | Count |
|---|---|
| Easy | 29 |
| Medium | 22 |
| Hard | 2 |
**By Tag:**
| Tag | Count |
|---|---|
| Array | 26 |
| Hash Table | 13 |
| String | 13 |
| Sorting | 12 |
| Two Pointers | 9 |
| Database | 8 |
| Counting | 6 |
| Stack | 6 |
| Depth-First Search | 5 |
| Breadth-First Search | 4 |
| Heap (Priority Queue) | 4 |
| Math | 4 |
| Binary Search | 4 |
| Tree | 3 |
| Binary Tree | 3 |
| Sliding Window | 3 |
| Design | 3 |
| Monotonic Stack | 3 |
| Linked List | 3 |
| Recursion | 3 |
| Dynamic Programming | 3 |
| Greedy | 3 |
| Divide and Conquer | 2 |
| Prefix Sum | 2 |
| Bucket Sort | 1 |
| Quickselect | 1 |
| Data Stream | 1 |
| Randomized | 1 |
| Trie | 1 |
| Union Find | 1 |
| Matrix | 1 |
| Simulation | 1 |
| Memoization | 1 |
| Combinatorics | 1 |
| Enumeration | 1 |
| String Matching | 1 |
## Solutions by Tag
### Tree
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 100-same-tree | Easy | [code](./Tree/easy/100-same-tree) | [leetcode](https://leetcode.com/problems/same-tree/) |
| 101-symmetric-tree | Easy | [code](./Tree/easy/101-symmetric-tree) | [leetcode](https://leetcode.com/problems/symmetric-tree/) |
| 111-minimum-depth-of-binary-tree | Easy | [code](./Tree/easy/111-minimum-depth-of-binary-tree) | [leetcode](https://leetcode.com/problems/minimum-depth-of-binary-tree/) |
### Depth-First Search
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 100-same-tree | Easy | [code](./Depth-First-Search/easy/100-same-tree) | [leetcode](https://leetcode.com/problems/same-tree/) |
| 101-symmetric-tree | Easy | [code](./Depth-First-Search/easy/101-symmetric-tree) | [leetcode](https://leetcode.com/problems/symmetric-tree/) |
| 111-minimum-depth-of-binary-tree | Easy | [code](./Depth-First-Search/easy/111-minimum-depth-of-binary-tree) | [leetcode](https://leetcode.com/problems/minimum-depth-of-binary-tree/) |
| 386-lexicographical-numbers | Medium | [code](./Depth-First-Search/medium/386-lexicographical-numbers) | [leetcode](https://leetcode.com/problems/lexicographical-numbers/) |
| 1753-path-with-minimum-effort | Medium | [code](./Depth-First-Search/medium/1753-path-with-minimum-effort) | [leetcode](https://leetcode.com/problems/path-with-minimum-effort/) |
### Breadth-First Search
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 100-same-tree | Easy | [code](./Breadth-First-Search/easy/100-same-tree) | [leetcode](https://leetcode.com/problems/same-tree/) |
| 101-symmetric-tree | Easy | [code](./Breadth-First-Search/easy/101-symmetric-tree) | [leetcode](https://leetcode.com/problems/symmetric-tree/) |
| 111-minimum-depth-of-binary-tree | Easy | [code](./Breadth-First-Search/easy/111-minimum-depth-of-binary-tree) | [leetcode](https://leetcode.com/problems/minimum-depth-of-binary-tree/) |
| 1753-path-with-minimum-effort | Medium | [code](./Breadth-First-Search/medium/1753-path-with-minimum-effort) | [leetcode](https://leetcode.com/problems/path-with-minimum-effort/) |
### Binary Tree
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 100-same-tree | Easy | [code](./Binary-Tree/easy/100-same-tree) | [leetcode](https://leetcode.com/problems/same-tree/) |
| 101-symmetric-tree | Easy | [code](./Binary-Tree/easy/101-symmetric-tree) | [leetcode](https://leetcode.com/problems/symmetric-tree/) |
| 111-minimum-depth-of-binary-tree | Easy | [code](./Binary-Tree/easy/111-minimum-depth-of-binary-tree) | [leetcode](https://leetcode.com/problems/minimum-depth-of-binary-tree/) |
### Database
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 1724-customer-who-visited-but-did-not-make-any-transactions | Easy | [code](./Database/easy/1724-customer-who-visited-but-did-not-make-any-transactions) | [leetcode](https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions/) |
| 1827-invalid-tweets | Easy | [code](./Database/easy/1827-invalid-tweets) | [leetcode](https://leetcode.com/problems/invalid-tweets/) |
| 1509-replace-employee-id-with-the-unique-identifier | Easy | [code](./Database/easy/1509-replace-employee-id-with-the-unique-identifier) | [leetcode](https://leetcode.com/problems/replace-employee-id-with-the-unique-identifier/) |
| 1908-recyclable-and-low-fat-products | Easy | [code](./Database/easy/1908-recyclable-and-low-fat-products) | [leetcode](https://leetcode.com/problems/recyclable-and-low-fat-products/) |
| 595-big-countries | Easy | [code](./Database/easy/595-big-countries) | [leetcode](https://leetcode.com/problems/big-countries/) |
| 584-find-customer-referee | Easy | [code](./Database/easy/584-find-customer-referee) | [leetcode](https://leetcode.com/problems/find-customer-referee/) |
| 197-rising-temperature | Easy | [code](./Database/easy/197-rising-temperature) | [leetcode](https://leetcode.com/problems/rising-temperature/) |
| 1153-product-sales-analysis-i | Easy | [code](./Database/easy/1153-product-sales-analysis-i) | [leetcode](https://leetcode.com/problems/product-sales-analysis-i/) |
### Hash Table
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 2025-redistribute-characters-to-make-all-strings-equal | Easy | [code](./Hash-Table/easy/2025-redistribute-characters-to-make-all-strings-equal) | [leetcode](https://leetcode.com/problems/redistribute-characters-to-make-all-strings-equal/) |
| 2163-kth-distinct-string-in-an-array | Easy | [code](./Hash-Table/easy/2163-kth-distinct-string-in-an-array) | [leetcode](https://leetcode.com/problems/kth-distinct-string-in-an-array/) |
| 594-longest-harmonious-subsequence | Easy | [code](./Hash-Table/easy/594-longest-harmonious-subsequence) | [leetcode](https://leetcode.com/problems/longest-harmonious-subsequence/) |
| 169-majority-element | Easy | [code](./Hash-Table/easy/169-majority-element) | [leetcode](https://leetcode.com/problems/majority-element/) |
| 1055-pairs-of-songs-with-total-durations-divisible-by-60 | Medium | [code](./Hash-Table/medium/1055-pairs-of-songs-with-total-durations-divisible-by-60) | [leetcode](https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/) |
| 347-top-k-frequent-elements | Medium | [code](./Hash-Table/medium/347-top-k-frequent-elements) | [leetcode](https://leetcode.com/problems/top-k-frequent-elements/) |
| 380-insert-delete-getrandom-o1 | Medium | [code](./Hash-Table/medium/380-insert-delete-getrandom-o1) | [leetcode](https://leetcode.com/problems/insert-delete-getrandom-o1/) |
| 141-linked-list-cycle | Easy | [code](./Hash-Table/easy/141-linked-list-cycle) | [leetcode](https://leetcode.com/problems/linked-list-cycle/) |
| 2204-find-subsequence-of-length-k-with-the-largest-sum | Easy | [code](./Hash-Table/easy/2204-find-subsequence-of-length-k-with-the-largest-sum) | [leetcode](https://leetcode.com/problems/find-subsequence-of-length-k-with-the-largest-sum/) |
| 500-keyboard-row | Easy | [code](./Hash-Table/easy/500-keyboard-row) | [leetcode](https://leetcode.com/problems/keyboard-row/) |
| 49-group-anagrams | Medium | [code](./Hash-Table/medium/49-group-anagrams) | [leetcode](https://leetcode.com/problems/group-anagrams/) |
| 3-longest-substring-without-repeating-characters | Medium | [code](./Hash-Table/medium/3-longest-substring-without-repeating-characters) | [leetcode](https://leetcode.com/problems/longest-substring-without-repeating-characters/) |
| 409-longest-palindrome | Easy | [code](./Hash-Table/easy/409-longest-palindrome) | [leetcode](https://leetcode.com/problems/longest-palindrome/) |
### String
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 2025-redistribute-characters-to-make-all-strings-equal | Easy | [code](./String/easy/2025-redistribute-characters-to-make-all-strings-equal) | [leetcode](https://leetcode.com/problems/redistribute-characters-to-make-all-strings-equal/) |
| 2163-kth-distinct-string-in-an-array | Easy | [code](./String/easy/2163-kth-distinct-string-in-an-array) | [leetcode](https://leetcode.com/problems/kth-distinct-string-in-an-array/) |
| 1351-replace-the-substring-for-balanced-string | Medium | [code](./String/medium/1351-replace-the-substring-for-balanced-string) | [leetcode](https://leetcode.com/problems/replace-the-substring-for-balanced-string/) |
| 2395-longest-binary-subsequence-less-than-or-equal-to-k | Medium | [code](./String/medium/2395-longest-binary-subsequence-less-than-or-equal-to-k) | [leetcode](https://leetcode.com/problems/longest-binary-subsequence-less-than-or-equal-to-k/) |
| 1751-slowest-key | Easy | [code](./String/easy/1751-slowest-key) | [leetcode](https://leetcode.com/problems/slowest-key/) |
| 500-keyboard-row | Easy | [code](./String/easy/500-keyboard-row) | [leetcode](https://leetcode.com/problems/keyboard-row/) |
| 49-group-anagrams | Medium | [code](./String/medium/49-group-anagrams) | [leetcode](https://leetcode.com/problems/group-anagrams/) |
| 273-integer-to-english-words | Hard | [code](./String/hard/273-integer-to-english-words) | [leetcode](https://leetcode.com/problems/integer-to-english-words/) |
| 3-longest-substring-without-repeating-characters | Medium | [code](./String/medium/3-longest-substring-without-repeating-characters) | [leetcode](https://leetcode.com/problems/longest-substring-without-repeating-characters/) |
| 28-find-the-index-of-the-first-occurrence-in-a-string | Easy | [code](./String/easy/28-find-the-index-of-the-first-occurrence-in-a-string) | [leetcode](https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string/) |
| 125-valid-palindrome | Easy | [code](./String/easy/125-valid-palindrome) | [leetcode](https://leetcode.com/problems/valid-palindrome/) |
| 409-longest-palindrome | Easy | [code](./String/easy/409-longest-palindrome) | [leetcode](https://leetcode.com/problems/longest-palindrome/) |
| 20-valid-parentheses | Easy | [code](./String/easy/20-valid-parentheses) | [leetcode](https://leetcode.com/problems/valid-parentheses/) |
### Counting
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 2025-redistribute-characters-to-make-all-strings-equal | Easy | [code](./Counting/easy/2025-redistribute-characters-to-make-all-strings-equal) | [leetcode](https://leetcode.com/problems/redistribute-characters-to-make-all-strings-equal/) |
| 2163-kth-distinct-string-in-an-array | Easy | [code](./Counting/easy/2163-kth-distinct-string-in-an-array) | [leetcode](https://leetcode.com/problems/kth-distinct-string-in-an-array/) |
| 594-longest-harmonious-subsequence | Easy | [code](./Counting/easy/594-longest-harmonious-subsequence) | [leetcode](https://leetcode.com/problems/longest-harmonious-subsequence/) |
| 169-majority-element | Easy | [code](./Counting/easy/169-majority-element) | [leetcode](https://leetcode.com/problems/majority-element/) |
| 1055-pairs-of-songs-with-total-durations-divisible-by-60 | Medium | [code](./Counting/medium/1055-pairs-of-songs-with-total-durations-divisible-by-60) | [leetcode](https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/) |
| 347-top-k-frequent-elements | Medium | [code](./Counting/medium/347-top-k-frequent-elements) | [leetcode](https://leetcode.com/problems/top-k-frequent-elements/) |
### Array
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 2163-kth-distinct-string-in-an-array | Easy | [code](./Array/easy/2163-kth-distinct-string-in-an-array) | [leetcode](https://leetcode.com/problems/kth-distinct-string-in-an-array/) |
| 594-longest-harmonious-subsequence | Easy | [code](./Array/easy/594-longest-harmonious-subsequence) | [leetcode](https://leetcode.com/problems/longest-harmonious-subsequence/) |
| 169-majority-element | Easy | [code](./Array/easy/169-majority-element) | [leetcode](https://leetcode.com/problems/majority-element/) |
| 1055-pairs-of-songs-with-total-durations-divisible-by-60 | Medium | [code](./Array/medium/1055-pairs-of-songs-with-total-durations-divisible-by-60) | [leetcode](https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/) |
| 347-top-k-frequent-elements | Medium | [code](./Array/medium/347-top-k-frequent-elements) | [leetcode](https://leetcode.com/problems/top-k-frequent-elements/) |
| 380-insert-delete-getrandom-o1 | Medium | [code](./Array/medium/380-insert-delete-getrandom-o1) | [leetcode](https://leetcode.com/problems/insert-delete-getrandom-o1/) |
| 1753-path-with-minimum-effort | Medium | [code](./Array/medium/1753-path-with-minimum-effort) | [leetcode](https://leetcode.com/problems/path-with-minimum-effort/) |
| 883-car-fleet | Medium | [code](./Array/medium/883-car-fleet) | [leetcode](https://leetcode.com/problems/car-fleet/) |
| 739-daily-temperatures | Medium | [code](./Array/medium/739-daily-temperatures) | [leetcode](https://leetcode.com/problems/daily-temperatures/) |
| 238-product-of-array-except-self | Medium | [code](./Array/medium/238-product-of-array-except-self) | [leetcode](https://leetcode.com/problems/product-of-array-except-self/) |
| 1184-car-pooling | Medium | [code](./Array/medium/1184-car-pooling) | [leetcode](https://leetcode.com/problems/car-pooling/) |
| 792-binary-search | Easy | [code](./Array/easy/792-binary-search) | [leetcode](https://leetcode.com/problems/binary-search/) |
| 2204-find-subsequence-of-length-k-with-the-largest-sum | Easy | [code](./Array/easy/2204-find-subsequence-of-length-k-with-the-largest-sum) | [leetcode](https://leetcode.com/problems/find-subsequence-of-length-k-with-the-largest-sum/) |
| 1751-slowest-key | Easy | [code](./Array/easy/1751-slowest-key) | [leetcode](https://leetcode.com/problems/slowest-key/) |
| 121-best-time-to-buy-and-sell-stock | Easy | [code](./Array/easy/121-best-time-to-buy-and-sell-stock) | [leetcode](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/) |
| 500-keyboard-row | Easy | [code](./Array/easy/500-keyboard-row) | [leetcode](https://leetcode.com/problems/keyboard-row/) |
| 26-remove-duplicates-from-sorted-array | Easy | [code](./Array/easy/26-remove-duplicates-from-sorted-array) | [leetcode](https://leetcode.com/problems/remove-duplicates-from-sorted-array/) |
| 88-merge-sorted-array | Easy | [code](./Array/easy/88-merge-sorted-array) | [leetcode](https://leetcode.com/problems/merge-sorted-array/) |
| 1669-minimum-cost-to-cut-a-stick | Hard | [code](./Array/hard/1669-minimum-cost-to-cut-a-stick) | [leetcode](https://leetcode.com/problems/minimum-cost-to-cut-a-stick/) |
| 150-evaluate-reverse-polish-notation | Medium | [code](./Array/medium/150-evaluate-reverse-polish-notation) | [leetcode](https://leetcode.com/problems/evaluate-reverse-polish-notation/) |
| 3430-count-days-without-meetings | Medium | [code](./Array/medium/3430-count-days-without-meetings) | [leetcode](https://leetcode.com/problems/count-days-without-meetings/) |
| 167-two-sum-ii-input-array-is-sorted | Medium | [code](./Array/medium/167-two-sum-ii-input-array-is-sorted) | [leetcode](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/) |
| 11-container-with-most-water | Medium | [code](./Array/medium/11-container-with-most-water) | [leetcode](https://leetcode.com/problems/container-with-most-water/) |
| 49-group-anagrams | Medium | [code](./Array/medium/49-group-anagrams) | [leetcode](https://leetcode.com/problems/group-anagrams/) |
| 15-3sum | Medium | [code](./Array/medium/15-3sum) | [leetcode](https://leetcode.com/problems/3sum/) |
| 1621-number-of-subsequences-that-satisfy-the-given-sum-condition | Medium | [code](./Array/medium/1621-number-of-subsequences-that-satisfy-the-given-sum-condition) | [leetcode](https://leetcode.com/problems/number-of-subsequences-that-satisfy-the-given-sum-condition/) |
### Sliding Window
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 594-longest-harmonious-subsequence | Easy | [code](./Sliding-Window/easy/594-longest-harmonious-subsequence) | [leetcode](https://leetcode.com/problems/longest-harmonious-subsequence/) |
| 1351-replace-the-substring-for-balanced-string | Medium | [code](./Sliding-Window/medium/1351-replace-the-substring-for-balanced-string) | [leetcode](https://leetcode.com/problems/replace-the-substring-for-balanced-string/) |
| 3-longest-substring-without-repeating-characters | Medium | [code](./Sliding-Window/medium/3-longest-substring-without-repeating-characters) | [leetcode](https://leetcode.com/problems/longest-substring-without-repeating-characters/) |
### Sorting
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 594-longest-harmonious-subsequence | Easy | [code](./Sorting/easy/594-longest-harmonious-subsequence) | [leetcode](https://leetcode.com/problems/longest-harmonious-subsequence/) |
| 169-majority-element | Easy | [code](./Sorting/easy/169-majority-element) | [leetcode](https://leetcode.com/problems/majority-element/) |
| 347-top-k-frequent-elements | Medium | [code](./Sorting/medium/347-top-k-frequent-elements) | [leetcode](https://leetcode.com/problems/top-k-frequent-elements/) |
| 883-car-fleet | Medium | [code](./Sorting/medium/883-car-fleet) | [leetcode](https://leetcode.com/problems/car-fleet/) |
| 1184-car-pooling | Medium | [code](./Sorting/medium/1184-car-pooling) | [leetcode](https://leetcode.com/problems/car-pooling/) |
| 2204-find-subsequence-of-length-k-with-the-largest-sum | Easy | [code](./Sorting/easy/2204-find-subsequence-of-length-k-with-the-largest-sum) | [leetcode](https://leetcode.com/problems/find-subsequence-of-length-k-with-the-largest-sum/) |
| 88-merge-sorted-array | Easy | [code](./Sorting/easy/88-merge-sorted-array) | [leetcode](https://leetcode.com/problems/merge-sorted-array/) |
| 1669-minimum-cost-to-cut-a-stick | Hard | [code](./Sorting/hard/1669-minimum-cost-to-cut-a-stick) | [leetcode](https://leetcode.com/problems/minimum-cost-to-cut-a-stick/) |
| 3430-count-days-without-meetings | Medium | [code](./Sorting/medium/3430-count-days-without-meetings) | [leetcode](https://leetcode.com/problems/count-days-without-meetings/) |
| 49-group-anagrams | Medium | [code](./Sorting/medium/49-group-anagrams) | [leetcode](https://leetcode.com/problems/group-anagrams/) |
| 15-3sum | Medium | [code](./Sorting/medium/15-3sum) | [leetcode](https://leetcode.com/problems/3sum/) |
| 1621-number-of-subsequences-that-satisfy-the-given-sum-condition | Medium | [code](./Sorting/medium/1621-number-of-subsequences-that-satisfy-the-given-sum-condition) | [leetcode](https://leetcode.com/problems/number-of-subsequences-that-satisfy-the-given-sum-condition/) |
### Divide and Conquer
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 169-majority-element | Easy | [code](./Divide-and-Conquer/easy/169-majority-element) | [leetcode](https://leetcode.com/problems/majority-element/) |
| 347-top-k-frequent-elements | Medium | [code](./Divide-and-Conquer/medium/347-top-k-frequent-elements) | [leetcode](https://leetcode.com/problems/top-k-frequent-elements/) |
### Heap (Priority Queue)
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 347-top-k-frequent-elements | Medium | [code](./Heap-Priority-Queue/medium/347-top-k-frequent-elements) | [leetcode](https://leetcode.com/problems/top-k-frequent-elements/) |
| 1753-path-with-minimum-effort | Medium | [code](./Heap-Priority-Queue/medium/1753-path-with-minimum-effort) | [leetcode](https://leetcode.com/problems/path-with-minimum-effort/) |
| 1184-car-pooling | Medium | [code](./Heap-Priority-Queue/medium/1184-car-pooling) | [leetcode](https://leetcode.com/problems/car-pooling/) |
| 2204-find-subsequence-of-length-k-with-the-largest-sum | Easy | [code](./Heap-Priority-Queue/easy/2204-find-subsequence-of-length-k-with-the-largest-sum) | [leetcode](https://leetcode.com/problems/find-subsequence-of-length-k-with-the-largest-sum/) |
### Bucket Sort
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 347-top-k-frequent-elements | Medium | [code](./Bucket-Sort/medium/347-top-k-frequent-elements) | [leetcode](https://leetcode.com/problems/top-k-frequent-elements/) |
### Quickselect
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 347-top-k-frequent-elements | Medium | [code](./Quickselect/medium/347-top-k-frequent-elements) | [leetcode](https://leetcode.com/problems/top-k-frequent-elements/) |
### Stack
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 937-online-stock-span | Medium | [code](./Stack/medium/937-online-stock-span) | [leetcode](https://leetcode.com/problems/online-stock-span/) |
| 155-min-stack | Medium | [code](./Stack/medium/155-min-stack) | [leetcode](https://leetcode.com/problems/min-stack/) |
| 883-car-fleet | Medium | [code](./Stack/medium/883-car-fleet) | [leetcode](https://leetcode.com/problems/car-fleet/) |
| 739-daily-temperatures | Medium | [code](./Stack/medium/739-daily-temperatures) | [leetcode](https://leetcode.com/problems/daily-temperatures/) |
| 150-evaluate-reverse-polish-notation | Medium | [code](./Stack/medium/150-evaluate-reverse-polish-notation) | [leetcode](https://leetcode.com/problems/evaluate-reverse-polish-notation/) |
| 20-valid-parentheses | Easy | [code](./Stack/easy/20-valid-parentheses) | [leetcode](https://leetcode.com/problems/valid-parentheses/) |
### Design
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 937-online-stock-span | Medium | [code](./Design/medium/937-online-stock-span) | [leetcode](https://leetcode.com/problems/online-stock-span/) |
| 155-min-stack | Medium | [code](./Design/medium/155-min-stack) | [leetcode](https://leetcode.com/problems/min-stack/) |
| 380-insert-delete-getrandom-o1 | Medium | [code](./Design/medium/380-insert-delete-getrandom-o1) | [leetcode](https://leetcode.com/problems/insert-delete-getrandom-o1/) |
### Monotonic Stack
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 937-online-stock-span | Medium | [code](./Monotonic-Stack/medium/937-online-stock-span) | [leetcode](https://leetcode.com/problems/online-stock-span/) |
| 883-car-fleet | Medium | [code](./Monotonic-Stack/medium/883-car-fleet) | [leetcode](https://leetcode.com/problems/car-fleet/) |
| 739-daily-temperatures | Medium | [code](./Monotonic-Stack/medium/739-daily-temperatures) | [leetcode](https://leetcode.com/problems/daily-temperatures/) |
### Data Stream
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 937-online-stock-span | Medium | [code](./Data-Stream/medium/937-online-stock-span) | [leetcode](https://leetcode.com/problems/online-stock-span/) |
### Math
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 380-insert-delete-getrandom-o1 | Medium | [code](./Math/medium/380-insert-delete-getrandom-o1) | [leetcode](https://leetcode.com/problems/insert-delete-getrandom-o1/) |
| 150-evaluate-reverse-polish-notation | Medium | [code](./Math/medium/150-evaluate-reverse-polish-notation) | [leetcode](https://leetcode.com/problems/evaluate-reverse-polish-notation/) |
| 273-integer-to-english-words | Hard | [code](./Math/hard/273-integer-to-english-words) | [leetcode](https://leetcode.com/problems/integer-to-english-words/) |
| 3201-distribute-candies-among-children-ii | Medium | [code](./Math/medium/3201-distribute-candies-among-children-ii) | [leetcode](https://leetcode.com/problems/distribute-candies-among-children-ii/) |
### Randomized
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 380-insert-delete-getrandom-o1 | Medium | [code](./Randomized/medium/380-insert-delete-getrandom-o1) | [leetcode](https://leetcode.com/problems/insert-delete-getrandom-o1/) |
### Linked List
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 206-reverse-linked-list | Easy | [code](./Linked-List/easy/206-reverse-linked-list) | [leetcode](https://leetcode.com/problems/reverse-linked-list/) |
| 141-linked-list-cycle | Easy | [code](./Linked-List/easy/141-linked-list-cycle) | [leetcode](https://leetcode.com/problems/linked-list-cycle/) |
| 21-merge-two-sorted-lists | Easy | [code](./Linked-List/easy/21-merge-two-sorted-lists) | [leetcode](https://leetcode.com/problems/merge-two-sorted-lists/) |
### Recursion
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 206-reverse-linked-list | Easy | [code](./Recursion/easy/206-reverse-linked-list) | [leetcode](https://leetcode.com/problems/reverse-linked-list/) |
| 21-merge-two-sorted-lists | Easy | [code](./Recursion/easy/21-merge-two-sorted-lists) | [leetcode](https://leetcode.com/problems/merge-two-sorted-lists/) |
| 273-integer-to-english-words | Hard | [code](./Recursion/hard/273-integer-to-english-words) | [leetcode](https://leetcode.com/problems/integer-to-english-words/) |
### Two Pointers
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 141-linked-list-cycle | Easy | [code](./Two-Pointers/easy/141-linked-list-cycle) | [leetcode](https://leetcode.com/problems/linked-list-cycle/) |
| 26-remove-duplicates-from-sorted-array | Easy | [code](./Two-Pointers/easy/26-remove-duplicates-from-sorted-array) | [leetcode](https://leetcode.com/problems/remove-duplicates-from-sorted-array/) |
| 88-merge-sorted-array | Easy | [code](./Two-Pointers/easy/88-merge-sorted-array) | [leetcode](https://leetcode.com/problems/merge-sorted-array/) |
| 167-two-sum-ii-input-array-is-sorted | Medium | [code](./Two-Pointers/medium/167-two-sum-ii-input-array-is-sorted) | [leetcode](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/) |
| 11-container-with-most-water | Medium | [code](./Two-Pointers/medium/11-container-with-most-water) | [leetcode](https://leetcode.com/problems/container-with-most-water/) |
| 15-3sum | Medium | [code](./Two-Pointers/medium/15-3sum) | [leetcode](https://leetcode.com/problems/3sum/) |
| 1621-number-of-subsequences-that-satisfy-the-given-sum-condition | Medium | [code](./Two-Pointers/medium/1621-number-of-subsequences-that-satisfy-the-given-sum-condition) | [leetcode](https://leetcode.com/problems/number-of-subsequences-that-satisfy-the-given-sum-condition/) |
| 28-find-the-index-of-the-first-occurrence-in-a-string | Easy | [code](./Two-Pointers/easy/28-find-the-index-of-the-first-occurrence-in-a-string) | [leetcode](https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string/) |
| 125-valid-palindrome | Easy | [code](./Two-Pointers/easy/125-valid-palindrome) | [leetcode](https://leetcode.com/problems/valid-palindrome/) |
### Trie
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 386-lexicographical-numbers | Medium | [code](./Trie/medium/386-lexicographical-numbers) | [leetcode](https://leetcode.com/problems/lexicographical-numbers/) |
### Binary Search
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 1753-path-with-minimum-effort | Medium | [code](./Binary-Search/medium/1753-path-with-minimum-effort) | [leetcode](https://leetcode.com/problems/path-with-minimum-effort/) |
| 792-binary-search | Easy | [code](./Binary-Search/easy/792-binary-search) | [leetcode](https://leetcode.com/problems/binary-search/) |
| 167-two-sum-ii-input-array-is-sorted | Medium | [code](./Binary-Search/medium/167-two-sum-ii-input-array-is-sorted) | [leetcode](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/) |
| 1621-number-of-subsequences-that-satisfy-the-given-sum-condition | Medium | [code](./Binary-Search/medium/1621-number-of-subsequences-that-satisfy-the-given-sum-condition) | [leetcode](https://leetcode.com/problems/number-of-subsequences-that-satisfy-the-given-sum-condition/) |
### Union Find
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 1753-path-with-minimum-effort | Medium | [code](./Union-Find/medium/1753-path-with-minimum-effort) | [leetcode](https://leetcode.com/problems/path-with-minimum-effort/) |
### Matrix
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 1753-path-with-minimum-effort | Medium | [code](./Matrix/medium/1753-path-with-minimum-effort) | [leetcode](https://leetcode.com/problems/path-with-minimum-effort/) |
### Prefix Sum
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 238-product-of-array-except-self | Medium | [code](./Prefix-Sum/medium/238-product-of-array-except-self) | [leetcode](https://leetcode.com/problems/product-of-array-except-self/) |
| 1184-car-pooling | Medium | [code](./Prefix-Sum/medium/1184-car-pooling) | [leetcode](https://leetcode.com/problems/car-pooling/) |
### Simulation
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 1184-car-pooling | Medium | [code](./Simulation/medium/1184-car-pooling) | [leetcode](https://leetcode.com/problems/car-pooling/) |
### Dynamic Programming
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 2395-longest-binary-subsequence-less-than-or-equal-to-k | Medium | [code](./Dynamic-Programming/medium/2395-longest-binary-subsequence-less-than-or-equal-to-k) | [leetcode](https://leetcode.com/problems/longest-binary-subsequence-less-than-or-equal-to-k/) |
| 121-best-time-to-buy-and-sell-stock | Easy | [code](./Dynamic-Programming/easy/121-best-time-to-buy-and-sell-stock) | [leetcode](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/) |
| 1669-minimum-cost-to-cut-a-stick | Hard | [code](./Dynamic-Programming/hard/1669-minimum-cost-to-cut-a-stick) | [leetcode](https://leetcode.com/problems/minimum-cost-to-cut-a-stick/) |
### Greedy
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 2395-longest-binary-subsequence-less-than-or-equal-to-k | Medium | [code](./Greedy/medium/2395-longest-binary-subsequence-less-than-or-equal-to-k) | [leetcode](https://leetcode.com/problems/longest-binary-subsequence-less-than-or-equal-to-k/) |
| 11-container-with-most-water | Medium | [code](./Greedy/medium/11-container-with-most-water) | [leetcode](https://leetcode.com/problems/container-with-most-water/) |
| 409-longest-palindrome | Easy | [code](./Greedy/easy/409-longest-palindrome) | [leetcode](https://leetcode.com/problems/longest-palindrome/) |
### Memoization
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 2395-longest-binary-subsequence-less-than-or-equal-to-k | Medium | [code](./Memoization/medium/2395-longest-binary-subsequence-less-than-or-equal-to-k) | [leetcode](https://leetcode.com/problems/longest-binary-subsequence-less-than-or-equal-to-k/) |
### Combinatorics
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 3201-distribute-candies-among-children-ii | Medium | [code](./Combinatorics/medium/3201-distribute-candies-among-children-ii) | [leetcode](https://leetcode.com/problems/distribute-candies-among-children-ii/) |
### Enumeration
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 3201-distribute-candies-among-children-ii | Medium | [code](./Enumeration/medium/3201-distribute-candies-among-children-ii) | [leetcode](https://leetcode.com/problems/distribute-candies-among-children-ii/) |
### String Matching
| Problem | Difficulty | Code | LeetCode |
|---|---|---|---|
| 28-find-the-index-of-the-first-occurrence-in-a-string | Easy | [code](./String-Matching/easy/28-find-the-index-of-the-first-occurrence-in-a-string) | [leetcode](https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string/) |