ref: https://leetcode.com/explore/learn/card/fun-with-arrays/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 26 | Remove Duplicates from Sorted Array | Python 3 | Easy |
| 27 | Remove Element | Python 3 | Easy |
| 88 | Merge Sorted Array | Python 3 | Easy |
| 283 | Move Zeroes | Python 3 | Easy |
| 414 | Third Maximum Number | Python 3 | Easy |
| 448 | Find All Numbers Disappeared in an Array | Python 3 | Easy |
| 485 | Max Consecutive Ones | Python 3 | Easy |
| 905 | Sort Array By Parity | Python 3 | Easy |
| 941 | Valid Mountain Array | Python 3 | Easy |
| 977 | Squares of a Sorted Array | Python 3 | Easy |
| 1089 | Duplicate Zeros | Python 3 | Easy |
| 1051 | Height Checker | Python 3 | Easy |
| 1295 | Find Numbers with Even Number of Digits | Python 3 | Easy |
| 1299 | Replace Elements with Greatest Element on Right Side | Python 3 | Easy |
| 1346 | Check If N and Its Double Exist | Python 3 | Easy |
ref: https://leetcode.com/explore/learn/card/array-and-string/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 14 | Longest Common Prefix | Python 3 | Easy |
| 28 | Implement strStr() | Python 3 | Easy |
| 54 | Spiral Matrix | Python 3 | Medium |
| 67 | Add Binary | Python 3 | Easy |
| 66 | Plus One | Python 3 | Easy |
| 118 | Pascal's Triangle | Python 3 | Easy |
| 151 | Reverse Words in a String | Python 3 | Medium |
| 167 | Two Sum II - Input array is sorted | Python 3 | Easy |
| 189 | Rotate Array | Python 3 | Medium |
| 209 | Minimum Size Subarray Sum | Python 3 | Medium |
| 498 | Diagonal Traverse | Python 3 | Medium |
| 557 | Reverse Words in a String III | Python 3 | Easy |
| 724 | Find Pivot Index | Python 3 | Easy |
| 747 | Largest Number At Least Twice of Others | Python 3 | Easy |
ref: https://leetcode.com/explore/learn/card/linked-list/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 2 | Add Two Numbers | Python 3 | Medium |
| 19 | Remove Nth Node From End of List | Python 3 | Medium |
| 21 | Merge Two Sorted Lists | Python 3 | Easy |
| 61 | Rotate List | Python 3 | Medium |
| 138 | Copy List with Random Pointer | Python 3 | Medium |
| 141 | Linked List Cycle | Python 3 | Easy |
| 142 | Linked List Cycle II | Python 3 | Medium |
| 160 | Intersection of Two Linked Lists | Python 3 | Easy |
| 203 | Remove Linked List Elements | Python 3 | Easy |
| 206 | Reverse Linked List | Python 3 | Easy |
| 234 | Palindrome Linked List | Python 3 | Easy |
| 328 | Odd Even Linked List | Python 3 | Medium |
| 430 | Flatten a Multilevel Doubly Linked List | Python 3 | Medium |
| 707 | Design Linked List | Python 3 | Medium |
ref: https://leetcode.com/explore/learn/card/data-structure-tree/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 94 | Binary Tree Inorder Traversal | Python 3 | Easy |
| 101 | Symmetric Tree | Python 3 | Easy |
| 102 | Binary Tree Level Order Traversal | Python 3 | Medium |
| 104 | Maximum Depth of Binary Tree | Python 3 | Easy |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | Python 3 | Medium |
| 106 | Construct Binary Tree from Inorder and Postorder Traversal | Python 3 | Medium |
| 112 | Path Sum | Python 3 | Easy |
| 116 | Populating Next Right Pointers in Each Node | Python 3 | Medium |
| 117 | Populating Next Right Pointers in Each Node II | Python 3 | Medium |
| 144 | Binary Tree Preorder Traversal | Python 3 | Easy |
| 145 | Binary Tree Postorder Traversal | Python 3 | Easy |
| 236 | Lowest Common Ancestor of a Binary Tree | Python 3 | Medium |
| 297 | Serialize and Deserialize Binary Tree | Python 3 | Hard |
ref: https://leetcode.com/explore/learn/card/n-ary-tree/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 429 | N-ary Tree Level Order Traversal | Python 3 | Medium |
| 559 | Maximum Depth of N-ary Tree | Python 3 | Easy |
| 589 | N-ary Tree Preorder Traversal | Python 3 | Easy |
| 590 | N-ary Tree Postorder Traversal | Python 3 | Easy |
ref: https://leetcode.com/explore/learn/card/introduction-to-data-structure-binary-search-tree/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 98 | Validate Binary Search Tree | Python 3 | Medium |
| 108 | Convert Sorted Array to Binary Search Tree | Python 3 | Easy |
| 110 | Balanced Binary Tree | Python 3 | Easy |
| 173 | Binary Search Tree Iterator | Python 3 | Medium |
| 220 | Contains Duplicate III | Python 3 | Medium |
| 235 | Lowest Common Ancestor of a Binary Search Tree | Python 3 | Easy |
| 450 | Delete Node in a BST | Python 3 | Medium |
| 701 | Insert into a Binary Search Tree | Python 3 | Medium |
| 703 | Kth Largest Element in a Stream | Python 3 | Easy |
ref: https://leetcode.com/explore/learn/card/recursion-i/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 21 | Merge Two Sorted Lists | Python 3 | Easy |
| 24 | Swap Nodes in Pairs | Python 3 | Medium |
| 50 | Pow(x, n) | Python 3 | Medium |
| 70 | Climbing Stairs | Python 3 | Easy |
| 95 | Unique Binary Search Trees II | Python 3 | Medium |
| 119 | Pascal's Triangle II | Python 3 | Easy |
| 206 | Reverse Linked List | Python 3 | Easy |
| 344 | Reverse String | Python 3 | Easy |
| 509 | Fibonacci Number | Python 3 | Easy |
| 700 | Search in a Binary Search Tree | Python 3 | Easy |
| 779 | K-th Symbol in Grammar | Python 3 | Medium |
ref: https://leetcode.com/explore/learn/card/recursion-ii
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 17 | Letter Combinations of a Phone Number | Python 3 | Medium |
| 22 | Generate Parentheses | Python 3 | Medium |
| 37 | Sudoku Solver | Python 3 | Hard |
| 46 | Permutations | Python 3 | Medium |
| 52 | N-Queens II | Python 3 | Hard |
| 77 | Combinations | Python 3 | Medium |
| 84 | Largest Rectangle in Histogram | Python 3 | Hard |
| 98 | Validate Binary Search Tree | Python 3 | Medium |
| 240 | Search a 2D Matrix II | Python 3 | Medium |
| 912 | Sort an Array | Python 3 | Medium |
ref: https://leetcode.com/explore/learn/card/hash-table
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 1 | Two Sum | Python 3 | Easy |
| 3 | Longest Substring Without Repeating Characters | Python 3 | Medium |
| 36 | Valid Sudoku | Python 3 | Medium |
| 49 | Group Anagrams | Python 3 | Medium |
| 136 | Single Number | Python 3 | Easy |
| 202 | Happy Number | Python 3 | Easy |
| 205 | Isomorphic Strings | Python 3 | Easy |
| 217 | Contains Duplicate | Python 3 | Easy |
| 219 | Contains Duplicate II | Python 3 | Easy |
| 347 | Top K Frequent Elements | Python 3 | Medium |
| 349 | Intersection of Two Arrays | Python 3 | Easy |
| 350 | Intersection of Two Arrays II | Python 3 | Easy |
| 380 | Insert Delete GetRandom O(1) | Python 3 | Medium |
| 387 | First Unique Character in a String | Python 3 | Easy |
| 454 | 4Sum II | Python 3 | Medium |
| 599 | Minimum Index Sum of Two Lists | Python 3 | Easy |
| 652 | Find Duplicate Subtrees | Python 3 | Medium |
| 705 | Design HashSet | Python 3 | Easy |
| 706 | Design HashMap | Python 3 | Easy |
| 771 | Jewels and Stones | Python 3 | Easy |
ref: https://leetcode.com/explore/learn/card/queue-stack
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 20 | Valid Parentheses | Python 3 | Easy |
| 133 | Clone Graph | Python 3 | Medium |
| 150 | Evaluate Reverse Polish Notation | Python 3 | Medium |
| 155 | Min Stack | Python 3 | Medium |
| 200 | Number of Islands | Python 3 | Medium |
| 225 | Implement Stack using Queues | Python 3 | Easy |
| 232 | Implement Queue using Stacks | Python 3 | Easy |
| 279 | Perfect Squares | Python 3 | Medium |
| 394 | Decode String | Python 3 | Medium |
| 494 | Target Sum | Python 3 | Medium |
| 542 | 01 Matrix | Python 3 | Medium |
| 622 | Design Circular Queue | Python 3 | Medium |
| 733 | Flood Fill | Python 3 | Easy |
| 739 | Daily Temperatures | Python 3 | Medium |
| 752 | Open the Lock | Python 3 | Medium |
| 841 | Keys and Rooms | Python 3 | Medium |
ref: https://leetcode.com/explore/learn/card/trie/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 208 | Implement Trie (Prefix Tree) | Python 3 | Medium |
| 211 | Design Add and Search Words Data Structure | Python 3 | Medium |
| 212 | Word Search II | Python 3 | Hard |
| 336 | Palindrome Pairs | Python 3 | Hard |
| 421 | Maximum XOR of Two Numbers in an Array | Python 3 | Medium |
| 648 | Replace Words | Python 3 | Medium |
| 677 | Map Sum Pairs) | Python 3 | Medium |
ref: https://leetcode.com/study-plan/algorithm/
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 33 | Search in Rotated Sorted Array | Python 3 | Medium |
| 34 | Find First and Last Position of Element in Sorted Array | Python 3 | Medium |
| 35 | Search Insert Position | Python 3 | Easy |
| 74 | Search a 2D Matrix | Python 3 | Medium |
| 153 | Find Minimum in Rotated Sorted Array | Python 3 | Medium |
| 162 | Find Peak Element | Python 3 | Medium |
| 278 | First Bad Version | Python 3 | Easy |
| 704 | Binary Search | Python 3 | Easy |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 15 | 3Sum | Python 3 | Medium |
| 844 | Backspace String Compare | Python 3 | Easy |
| 876 | Middle of the Linked List | Python 3 | Easy |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 438 | Find All Anagrams in a String | Python 3 | Medium |
| 567 | Permutation in String | Python 3 | Medium |
| 713 | Subarray Product Less Than K | Python 3 | Medium |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 130 | Surrounded Regions | Python 3 | Medium |
| 547 | Number of Provinces | Python 3 | Medium |
| 572 | Subtree of Another Tree | Python 3 | Easy |
| 617 | Merge Two Binary Trees | Python 3 | Easy |
| 695 | Max Area of Island | Python 3 | Medium |
| 797 | All Paths From Source to Target | Python 3 | Medium |
| 994 | Rotting Oranges | Python 3 | Medium |
| 1091 | Shortest Path in Binary Matrix | Python 3 | Medium |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 39 | Combination Sum | Python 3 | Medium |
| 40 | Combination Sum II | Python 3 | Medium |
| 47 | Permutations II | Python 3 | Medium |
| 78 | Subsets | Python 3 | Medium |
| 79 | Word Search | Python 3 | Medium |
| 90 | Subsets II | Python 3 | Medium |
| 784 | Letter Case Permutation | Python 3 | Medium |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 5 | Longest Palindromic Substring | Python 3 | Medium |
| 45 | Jump Game II | Python 3 | Medium |
| 55 | Jump Game | Python 3 | Medium |
| 62 | Unique Paths | Python 3 | Medium |
| 91 | Decode Ways | Python 3 | Medium |
| 139 | Word Break | Python 3 | Medium |
| 198 | House Robber | Python 3 | Medium |
| 213 | House Robber II | Python 3 | Medium |
| 300 | Longest Increasing Subsequence | Python 3 | Medium |
| 413 | Arithmetic Slices | Python 3 | Medium |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 1509 | Minimum Difference Between Largest and Smallest Value in Three Moves | Python 3 | Medium |
| 1525 | Number of Good Ways to Split a String | Python 3 | Medium |