| 1 | Two Sum | — | Easy | ArrayHash Table | 56% | |
| 2 | Add Two Numbers | — | Medium | Linked ListMathRecursion | 46% | |
| 3 | Longest Substring Without Repeating Characters | — | Medium | Hash TableStringSliding Window | 37% | |
| 4 | Median of Two Sorted Arrays | — | Hard | ArrayBinary SearchDivide and Conquer | 44% | |
| 5 | Longest Palindromic Substring | — | Medium | Two PointersStringDynamic Programming | 36% | |
| 7 | Reverse Integer | — | Medium | Math | 30% | |
| 10 | Regular Expression Matching | — | Hard | StringDynamic ProgrammingRecursion | 29% | |
| 11 | Container With Most Water | — | Medium | ArrayTwo PointersGreedy | 58% | |
| 15 | 3Sum | — | Medium | ArrayTwo PointersSorting | 37% | |
| 17 | Letter Combinations of a Phone Number | — | Medium | Hash TableStringBacktracking | 64% | |
| 19 | Remove Nth Node From End of List | — | Medium | Linked ListTwo Pointers | 49% | |
| 20 | Valid Parentheses | — | Easy | StringStack | 42% | |
| 21 | Merge Two Sorted Lists | — | Easy | Linked ListRecursion | 67% | |
| 22 | Generate Parentheses | — | Medium | StringDynamic ProgrammingBacktracking | 77% | |
| 23 | Merge k Sorted Lists | — | Hard | Linked ListDivide and ConquerHeap (Priority Queue) | 56% | |
| 25 | Reverse Nodes in k-Group | — | Hard | Linked ListRecursion | 63% | |
| 33 | Search in Rotated Sorted Array | — | Medium | ArrayBinary Search | 43% | |
| 36 | Valid Sudoku | — | Medium | ArrayHash TableMatrix | 62% | |
| 39 | Combination Sum | — | Medium | ArrayBacktracking | 74% | |
| 40 | Combination Sum II | — | Medium | ArrayBacktracking | 58% | |
| 42 | Trapping Rain Water | — | Hard | ArrayTwo PointersDynamic Programming | 65% | |
| 43 | Multiply Strings | — | Medium | MathStringSimulation | 42% | |
| 45 | Jump Game II | — | Medium | ArrayDynamic ProgrammingGreedy | 41% | |
| 46 | Permutations | — | Medium | ArrayBacktracking | 81% | |
| 48 | Rotate Image | — | Medium | ArrayMathMatrix | 78% | |
| 49 | Group Anagrams | — | Medium | ArrayHash TableString | 71% | |
| 50 | Pow(x, n) | — | Medium | MathRecursion | 37% | |
| 51 | N-Queens | — | Hard | ArrayBacktracking | 72% | |
| 53 | Maximum Subarray | — | Medium | ArrayDivide and ConquerDynamic Programming | 52% | |
| 54 | Spiral Matrix | — | Medium | ArrayMatrixSimulation | 54% | |
| 55 | Jump Game | — | Medium | ArrayDynamic ProgrammingGreedy | 39% | |
| 56 | Merge Intervals | — | Medium | ArraySorting | 49% | |
| 57 | Insert Interval | — | Medium | Array | 43% | |
| 62 | Unique Paths | — | Medium | MathDynamic ProgrammingCombinatorics | 66% | |
| 66 | Plus One | — | Easy | ArrayMath | 47% | |
| 70 | Climbing Stairs | — | Easy | MathDynamic ProgrammingMemoization | 53% | |
| 72 | Edit Distance | — | Medium | StringDynamic Programming | 59% | |
| 73 | Set Matrix Zeroes | — | Medium | ArrayHash TableMatrix | 60% | |
| 74 | Search a 2D Matrix | — | Medium | ArrayBinary SearchMatrix | 52% | |
| 76 | Minimum Window Substring | — | Hard | Hash TableStringSliding Window | 45% | |
| 78 | Subsets | — | Medium | ArrayBacktrackingBit Manipulation | 81% | |
| 79 | Word Search | — | Medium | ArrayStringBacktracking | 45% | |
| 84 | Largest Rectangle in Histogram | — | Hard | ArrayStackMonotonic Stack | 47% | |
| 90 | Subsets II | — | Medium | ArrayBacktrackingBit Manipulation | 59% | |
| 91 | Decode Ways | — | Medium | StringDynamic Programming | 36% | |
| 97 | Interleaving String | — | Medium | StringDynamic Programming | 42% | |
| 98 | Validate Binary Search Tree | — | Medium | TreeDepth-First SearchBinary Search Tree | 34% | |
| 100 | Same Tree | — | Easy | TreeDepth-First SearchBreadth-First Search | 65% | |
| 102 | Binary Tree Level Order Traversal | — | Medium | TreeBreadth-First SearchBinary Tree | 70% | |
| 104 | Maximum Depth of Binary Tree | — | Easy | TreeDepth-First SearchBreadth-First Search | 77% | |