LeetCode study plan
My solution for LeetCode problems using Python.
- Techniques
- Programming paradigms
- Data Structures
- Algorithms
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 136 | Single Number | Easy | . | . | |
| 190 | Reverse Bits | Easy | . | . | |
| 191 | Number of 1 Bits | Easy | O(1) | O(1) | Kernighan’s Algorithm |
| 201 | Bitwise AND of Numbers Range | Medium | O(1) | O(1) | |
| 231 | Power of Two | Easy | . | . |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 11 | Container With Most Water | Medium | O(n) | O(1) | TwoPointers |
| 15 | 3Sum | Medium | O(n) | O(1) | TwoPointers |
| 125 | Valid Palindrome | Easy | O(n) | O(1) | TwoPointers |
| 167 | Two Sum II - Input array is sorted | Medium | O(n) | O(1) | HashMap, TwoPointers |
| 283 | Move Zeroes | Easy | O(n) | O(1) | TwoPointers |
| 344 | Reverse String | Easy | O(n) | O(1) | TwoPointers |
| 581 | Shortest Unsorted Continuous Subarray | Medium | O(n) | O(1) | TwoPointers |
| 647 | Palindromic Substrings | Medium | O(n^2) | O(1) | TwoPointers |
| 844 | Backspace String Compare | Easy | O(n) | O(1) | TwoPointers backwards |
| 905 | Sort Array By Parity | Easy | O(n) | O(1) | |
| 977 | Squares of a Sorted Array | Easy | O(n) | O(1) | TwoPointers |
| 1695 | Maximum Erasure Value | Medium | O(n) | O(n) | TwoPointers |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 17 | Letter Combinations of a Phone Number | Medium | O(n * 4^n) | O(1) | Backtraking |
| 22 | Generate Parentheses | Medium | O(2^(n+1)) | O(n) | Backtraking |
| 39 | Combination Sum | Medium | O(2^t) | O(1) | DFS |
| 40 | Combination Sum II | Medium | O(n^2) | O(n^2) | Backtraking |
| 46 | Permutations | Medium | . | . | |
| 47 | Permutations II | Medium | O(n * 2^n) | O(n) | DFS |
| 51 | N-Queens | Hard | O(n^n) | O(n*n) | |
| 52 | N-Queens | Hard | O(n^n) | O(1) | |
| 77 | Combinations | Medium | . | . | |
| 78 | Subsets | Medium | O(n*2^n) | O(n*2^n) | |
| 79 | Word Search | Medium | . | . | |
| 90 | Subsets | Medium | O(n*2^n) | O(n*2^n) | |
| 216 | Combination Sum III | Medium | O(k * C(n, k)) | O(k) | DFS |
| 784 | Letter Case Permutation | Medium | . | . |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 45 | Jump Game II | Medium | O(n^2) | O(n) | |
| 62 | Unique Paths | Medium | O(n * m) | O(n) | |
| 70 | Climbing Stairs | Easy | . | . | |
| 72 | Edit Distance | Hard | O(n * m) | O(n * m) | |
| 120 | Triangle | Medium | . | . | |
| 198 | House Robber | Medium | O(n) | O(1) | |
| 213 | House Robber II | Medium | O(n) | O(1) | |
| 300 | Longest Increasing Subsequence | Medium | O(n^2) | O(n) | |
| 303 | Range Sum Query - Immutable | Easy | O(n) init, O(1) query | O(n) | prefix_sum |
| 304 | Range Sum Query 2D - Immutable | Medium | O(n^2) init, O(1) query | O(n^2) | prefix_sum |
| 307 | Range Sum Query - Mutable | Medium | . | . | |
| 322 | Coin Change | Medium | O(m * n) | O(m) | |
| 343 | Integer Break | Medium | O(n^2) | O(n) | |
| 413 | Arithmetic Slices | Medium | O(n) | O(1) | |
| 583 | Delete Operation for Two Strings | Medium | O(m * n) | O(m * n) | |
| 673 | Number of Longest Increasing Subsequence | Medium | O(n^2) | O(n) | |
| 1143 | Longest Common Subsequence | Medium | O(n * m) | O(n * m) | |
| 1641 | Count Sorted Vowel Strings | Medium | O(n) | O(1) | |
| 1658 | Minimum Operations to Reduce X to Zero | Medium | O(n) | O(n) | prefix_sum |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 42 | Trapping Rain Water | Hard | . | . | |
| 55 | Jump Game | Medium | O(n) | O(1) | |
| 134 | Gas Station | Medium | . | . |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 518 | Coin Change 2 | Medium | O(m * n) | O(m * n) | DFS |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 26 | Remove Duplicates from Sorted Array | Easy | . | . | |
| 121 | Best Time to Buy and Sell Stock | Easy | . | . | SlidingWindow |
| 128 | Longest Consecutive Sequence | O(α(n)) | O(n) | DSU, HashSet, HashMap | |
| 169 | Majority Element | Easy | . | . | |
| 189 | Rotate Array | Medium | . | . | |
| 209 | Minimum Size Subarray Sum | Medium | O(n) | O(1) | TwoPointers |
| 215 | Kth Largest Element in an Array | Medium | . | . | |
| 238* | Product of Array Except Self | Medium | O(n) | O(1) | |
| 384 | Shuffle an Array | Medium | O(n) | O(n) | Fisher-Yates |
| 424 | Longest Repeating Character Replacement | Medium | O(n) | O(1) | SlidingWindow |
| 704 | Binary Search | Easy | . | . | |
| 713 | Subarray Product Less Than K | Medium | O(n) | O(1) | TwoPointers |
| 807 | Max Increase to Keep City Skyline | Medium | . | . | |
| 986 | Interval List Intersections | Medium | O(n+m) | O(1) | TwoPointers |
| 1337 | The K Weakest Rows in a Matrix | Easy | . | . |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 347 | Top K Frequent Elements | Medium | O(n) | O(n) | |
| 621 | Task Scheduler | Medium | O(n) | O(1) | |
| 630 | Course Schedule III | Hard | O(n log n) | O(n) | |
| 703 | Kth Largest Element in a Stream | Easy | . | . | |
| 1046 | Last Stone Weight | Easy | . | . |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 130 | Surrounded Regions | Medium | O(m*n) | O(1) | DFS |
| 133 | Clone Graph | Medium | . | . | DFS |
| 200 | Number of Island | Medium | . | . | DFS, BFS |
| 207 | Course Schedule | Medium | . | . | DFS cycle |
| 210 | Course Schedule II | Medium | . | . | |
| 329 | Longest Increasing Path in a Matrix | hard | O(m * n) | O(m * n) | DFS and memoization |
| 417 | Pacific Atlantic Water Flow | Medium | . | . | DFS and Sets |
| 542 | 01 Matrix | Medium | . | . | BFS, DP |
| 547 | Number of Provinces | Medium | . | . | DFS |
| 695 | Max Area of Island | Medium | . | . | |
| 733 | Flood Fill | Easy | . | . | |
| 797 | All Paths From Source to Target | Medium | . | . | |
| 841 | Keys and Rooms | Medium | . | . | |
| 934 | Shortest Bridge | Medium | . | . | BFS multi source and DFS |
| 994 | Rotting Oranges | Medium | . | . | BFS multi source |
| 997 | Find the Town Judge | Easy | . | . | |
| 1020 | Number of Enclaves | Medium | . | . | DFS |
| 1091 | Shortest Path in Binary Matrix | Medium | . | . | BFS |
| 1162 | As Far from Land as Possible | Medium | . | . | BFS multi source |
| 1192 | Critical Connections in a Network | Hard | O(v+e) | O(v+e) | Tarjan |
| 1254 | Number of Closed Islands | Medium | . | . | DFS 2 pass |
| 1319 | Number of Operations to Make Network Connected | Medium | . | . | DFS |
| 1791 | Find Center of Star Graph | Easy | . | . | |
| 1905 | Count Sub Islands | Medium | . | . | |
| 1926 | Nearest Exit from Entrance in Maze | Medium | . | . | |
| 1971 | Find if Path Exists in Graph | Easy | . | . | DFS_(i, r) and BFS_(i, r) |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 1 | Two Sum | Easy | O(n) | O(n) | |
| 13 | Roman to Integer | Easy | . | . | |
| 36 | Valid Sudoku | Medium | . | . | |
| 49 | Group Anagrams | Medium | O(n*m) | O(n*m) | |
| 202 | Happy Number | Easy | O(?) | O(?) |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 2 | Add Two Numbers | Medium | . | . | |
| 19 | Remove Nth Node From End of List | Medium | O(n) | O(1) | TwoPointers |
| 21 | Merge Two Sorted Lists | Easy | . | . | |
| 82 | Remove Duplicates from Sorted List II | Medium | O(n) | O(1) | TwoPointers |
| 138 | Copy List with Random Pointer | Medium | . | . | |
| 141 | Linked List Cycle | Easy | . | . | |
| 143 | Reorder List | Medium | O(n) | O(1) | |
| 160 | Intersection of Two Linked Lists | Easy | . | . | |
| 876 | Middle of the Linked List | Easy | . | . | TwoPointers |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 239 | Sliding Window Maximum | Hard | . | . | MaxQueue |
| 341 | Flatten Nested List Iterator | Medium | . | . | Recursion |
| 950 | Medium | O(n) | O(n) | ||
| 1438 | Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit | Medium | . | . | MaxQueue |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 20 | Valid Parentheses | Easy | . | . | |
| 32 | Longest Valid Parentheses | Hard | O(n) | O(n) | |
| 71 | Simplify Path | Medium | . | . | |
| 84 | Largest Rectangle in Histogram | Hard | O(n) | O(1) | |
| 150 | Evaluate Reverse Polish Notation | Medium | . | . | |
| 155 | Min Stack | Easy | . | . | |
| 224 | Basic Calculator | Hard | . | . | |
| 225 | Implement Stack using Queues | Easy | . | . | |
| 739 | Daily Temperatures | Medium | O(n) | O(m) | MinStack |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 3 | Longest Substring Without Repeating Characters | Medium | . | . | Sliding Window |
| 5 | Longest Palindromic Substring | Medium | . | . | |
| 8 | String to Integer (atoi) | Medium | . | . | |
| 91 | Decode Ways | Medium | O(n) | O(1) | dfs, dp |
| 139 | Word Break | Medium | O(n*m) | O(n) | dp |
| 208 | Implement Trie (Prefix Tree) | Medium | O(n) | O(n*m) | Trie |
| 438 | Find All Anagrams in a String | Medium | O(n) | O(m) | HashMap, TwoPointers |
| 557 | Reverse Words in a String III | Easy | . | . | |
| 567 | Permutation in String | Medium | . | . | Sliding Window |
| 745 | Prefix and Suffix Search | Hard | O(k*n) | O(k*n) | Trie |
| 771 | Jewels and Stones | Easy | . | . | |
| 820 | Short Encoding of Words | Medium | O(k*n) | O(k*n) | Trie |
| 1344 | Angle Between Hands of a Clock | Medium | . | . | |
| 1689 | Partitioning Into Minimum Number Of Deci-Binary Numbers | Medium | O(n) | O(1) |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 94 | Binary Tree Inorder Traversal | Easy | . | . | |
| 98 | Validate Binary Search Tree | Medium | . | . | |
| 101 | Symmetric Tree | Easy | . | . | |
| 102 | Binary Tree Level Order Traversal | Medium | . | . | BFS |
| 104 | Maximum Depth of Binary Tree | Easy | . | . | |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | Medium | . | . | |
| 116 | Populating Next Right Pointers in Each Node | Easy | . | . | |
| 117 | Populating Next Right Pointers in Each Node II | Easy | O(n) | O(n) | BFS |
| 211 | Design Add and Search Words Data Structure | Medium | . | . | |
| 212 | Word Search II | Medium | . | . | |
| 230 | Kth Smallest Element in a BST | Medium | O(n) | O(n) | InOrder |
| 236 | Lowest Common Ancestor of a Binary Tree | Medium | . | . | |
| 572 | Subtree of Another Tree | Easy | O(n * m) | O(1) | Recursion |
| 617 | Merge Two Binary Trees | Medium | . | . | |
| 968 | Binary Tree Cameras | Hard | O(n) | O(h) | DFS |
| 1379 | Find a Corresponding Node of a Binary Tree in a Clone of That Tree | Medium | O(n) | O(n) | DFS |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 33 | Search in Rotated Sorted Array | Medium | O(log n) | O(1) | |
| 35 | Search Insert Position | Easy | . | . | |
| 74 | Search a 2D Matrix | Medium | O(log n) | O(1) | |
| 153 | Find Minimum in Rotated Sorted Array | Medium | O(log n) | O(1) | |
| 162 | Find Peak Element | Medium | O(log n) | O(1) | |
| 278 | First Bad Version | Easy | . | . | |
| 374 | Guess Number Higher or Lower | Easy | O(log n) | O(1) | |
| 669 | Trim a Binary Search Tree | Medium | O(n) | O(n) | |
| 704 | Binary Search | Easy | . | . |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 146 | LRU Cache | Medium | . | . |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 56 | Merge Intervals | O(nlogn) | O(1) | Intervals | |
| 57 | Insert Interval | Medium | O(n) | O(1) | Intervals |
| 88 | Merge Sorted Array | Easy | . | . | |
| 435 | Non-overlapping Intervals | Medium | O(nlogn) | O(1) | Intervals |
| 1851 | Minimum Interval to Include Each Query | Hard | O(nlogn + qlogq) | O(n) | MinHeap |
| # | Title | Level | Time | Space | Tags |
|---|---|---|---|---|---|
| 743 | Network Delay Time | Medium | O(V*logE) | O(E) | Djikstra |