- +: Solved within 1h
- -: Solved over 1h
- !: Got help from the solution or Found a better solution
- ?: Still don't understand the solution (should try again)
| Index | Name | Category | from | answer | note |
|---|---|---|---|---|---|
| 1 | Fine Pivot Index | array | LeetCode | link | +! |
| 2 | Largest Number At Least Twice of Others | array | LeetCode | link | +! |
| 3 | Plus One | array | LeetCode | link | + |
| 4 | Diagonal Traverse | array | LeetCode | link | +! |
| 5 | Spiral Matrix | array | LeetCode | link | + |
| 6 | Pascal's Triangle | array | LeetCode | link | +! |
| 7 | Add Binary | string | LeetCode | link | + |
| 8 | Implement strStr() | string | LeetCode | link | ! |
| 9 | Longest Common Prefix | string | LeetCode | link | +! |
| 10 | Reverse String | Two-Pointer Technique | LeetCode | link | +! |
| 11 | Array Partition I | Two-Pointer Technique | LeetCode | link | +! |
| 12 | Two Sum II | Two-Pointer Technique | LeetCode | link | +! |
| 13 | Remove Element | Two-Pointer Technique | LeetCode | link | +! |
| 14 | Max Consecutive Ones | Two-Pointer Technique | LeetCode | link | + |
| 15 | Minimum Size Subarray Sum | Two-Pointer Technique | LeetCode | link | + |
| 16 | Rotate Array | String and Array - Conclusion | LeetCode | link | + |
| 17 | Pascal's Triangle II | String and Array - Conclusion | LeetCode | link | + |
| 18 | Reverse Words in a String | String and Array - Conclusion | LeetCode | link | +! |
| 19 | Reverse Words in a String III | String and Array - Conclusion | LeetCode | link | + |
| 20 | Move Zeroes | String and Array - Conclusion | LeetCode | link | + |
| 21 | Design Linked List | Singly Linked List | LeetCode | link | + |
| 22 | Linked List Cycle | Two Pointer Linked List | LeetCode | link | + |
| 23 | Binary Tree Preorder Traversal | Binary Tree | LeetCode | link | + |
| 24 | Binary Tree Inorder Traversal | Binary Tree | LeetCode | link | + |
| 25 | Binary Tree Postorder Traversal | Binary Tree | LeetCode | link | + |
| 26 | Binary Tree Level Order Traversal | Binary Tree | LeetCode | link | + |
| 27 | Maximum Depth of Binary Tree | Binary Tree | LeetCode | link | + |
| 28 | Symmetric Tree | Binary Tree | LeetCode | link | + |
| 29 | Path Sum | Binary Tree | LeetCode | link | +! |
| 30 | Construct Binary Tree from Inorder and Postorder Traversal | Binary Tree | LeetCode | link | +! |
| 31 | Construct Binary Tree from Preorder and Inorder Traversal | Binary Tree | LeetCode | link | + |
| 32 | Populating Next Right Pointers in Each Node | Binary Tree | LeetCode | link | + |
| 33 | Populating Next Right Pointers in Each Node II | Binary Tree | LeetCode | link | + |
| 34 | Lowest Common Ancestor of a Binary Tree | Binary Tree | LeetCode | link | + |
| 35 | Serialize and Deserialize Binary Tree | Binary Tree | LeetCode | link | +! |
| 36 | Find Numbers with Even Number of Digits | Arrays 101 | LeetCode | link | + |
| 37 | Squares of a Sorted Array | Arrays 101 | LeetCode | link | + |
| 38 | Duplicate Zeros | Arrays 101 | LeetCode | link | + |
| 39 | Merge Sorted Array | Arrays 101 | LeetCode | link | + |
| 40 | Check If N and Its Double Exist | Arrays 101 | LeetCode | link | + |
| 41 | Valid Mountain Array | Arrays 101 | LeetCode | link | + |
| 42 | Replace Elements with Greatest Element on Right Side | Arrays 101 | LeetCode | link | + |
| 43 | Sort Array By Parity | Arrays 101 | LeetCode | link | + |
| 44 | Height Checker | Arrays 101 | LeetCode | link | + |
| 45 | Third Maximum Number | Arrays 101 | LeetCode | link | + |
| 46 | Find All Numbers Disappeared in an Array | Arrays 101 | LeetCode | link | + |
| 47 | Squares of a Sorted Array | Arrays 101 | LeetCode | link | + |
| 48 | Swap Nodes in Pairs | Recursion | LeetCode | link | + |
| 48 | Reverse Linked List | Recursion | LeetCode | link | +! |
| 49 | Search in a Binary Search Tree | Recursion | LeetCode | link | + |
| 50 | Fibonacci Number | Recursion | LeetCode | link | + |
| 51 | Climbing Stairs | Recursion | LeetCode | link | + |
| 52 | Pow(x, n) | Recursion | LeetCode | link | + |
| 53 | Merge Two Sorted Lists | Recursion | LeetCode | link | + |
| 54 | K-th Symbol in Grammar | Recursion | LeetCode | link | + |
| 54 | Unique Binary Search Trees II | Recursion | LeetCode | link | ! |
| 55 | Sort an Array | Recursion | LeetCode | link | + |
| 56 | Validate Binary Search Tree | Recursion | LeetCode | link | + |
| 57 | Search a 2D Matrix II | Recursion | LeetCode | link | + |
| 58 | N-queens II | Recursion | LeetCode | link | + |
| 59 | Sudoku Solver | Recursion | LeetCode | link | +! |
| 60 | Combinations | Recursion | LeetCode | link | + |
| 61 | Same Tree | Recursion | LeetCode | link | + |
| 62 | Generate Parentheses | Recursion | LeetCode | link | + |
| 63 | Largest Rectangle in Histogram | Recursion | LeetCode | link | ! |
| 64 | Permutations | Recursion | LeetCode | link | + |