| 1 | Two Sum | — | Easy | ArrayHash Table | 56% | |
| 3 | Longest Substring Without Repeating Characters | — | Medium | Hash TableStringSliding Window | 37% | |
| 5 | Longest Palindromic Substring | — | Medium | Two PointersStringDynamic Programming | 36% | |
| 11 | Container With Most Water | — | Medium | ArrayTwo PointersGreedy | 58% | |
| 15 | 3Sum | — | Medium | ArrayTwo PointersSorting | 37% | |
| 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% | |
| 23 | Merge k Sorted Lists | — | Hard | Linked ListDivide and ConquerHeap (Priority Queue) | 56% | |
| 33 | Search in Rotated Sorted Array | — | Medium | ArrayBinary Search | 43% | |
| 39 | Combination Sumread | — | Medium | ArrayBacktracking | 74% | |
| 48 | Rotate Image | — | Medium | ArrayMathMatrix | 78% | |
| 49 | Group Anagrams | — | Medium | ArrayHash TableString | 71% | |
| 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% | |
| 70 | Climbing Stairs | — | Easy | MathDynamic ProgrammingMemoization | 53% | |
| 73 | Set Matrix Zeroes | — | Medium | ArrayHash TableMatrix | 60% | |
| 76 | Minimum Window Substring | — | Hard | Hash TableStringSliding Window | 45% | |
| 79 | Word Search | — | Medium | ArrayStringBacktracking | 45% | |
| 91 | Decode Ways | — | Medium | StringDynamic Programming | 36% | |
| 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% | |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | — | Medium | ArrayHash TableDivide and Conquer | 67% | |
| 121 | Best Time to Buy and Sell Stock | — | Easy | ArrayDynamic Programming | 55% | |
| 124 | Binary Tree Maximum Path Sum | — | Hard | Dynamic ProgrammingTreeDepth-First Search | 41% | |
| 125 | Valid Palindrome | — | Easy | Two PointersString | 51% | |
| 128 | Longest Consecutive Sequence | — | Medium | ArrayHash TableUnion Find | 47% | |
| 133 | Clone Graphread | — | Medium | Hash TableDepth-First SearchBreadth-First Search | 62% | |
| 139 | Word Break | — | Medium | ArrayHash TableString | 48% | |
| 141 | Linked List Cycle | — | Easy | Hash TableLinked ListTwo Pointers | 52% | |
| 143 | Reorder List | — | Medium | Linked ListTwo PointersStack | 62% | |
| 152 | Maximum Product Subarray | — | Medium | ArrayDynamic Programming | 35% | |
| 153 | Find Minimum in Rotated Sorted Array | — | Medium | ArrayBinary Search | 52% | |
| 190 | Reverse Bits | — | Easy | Divide and ConquerBit Manipulation | 63% | |
| 191 | Number of 1 Bits | — | Easy | Divide and ConquerBit Manipulation | 74% | |
| 198 | House Robber | — | Medium | ArrayDynamic Programming | 52% | |
| 200 | Number of Islands | — | Medium | ArrayDepth-First SearchBreadth-First Search | 62% | |
| 206 | Reverse Linked List | — | Easy | Linked ListRecursion | 79% | |
| 207 | Course Scheduleread | — | Medium | Depth-First SearchBreadth-First SearchGraph | 49% | |
| 208 | Implement Trie (Prefix Tree)read | — | Medium | Hash TableStringDesign | 68% | |
| 211 | Design Add and Search Words Data Structureread | — | Medium | StringDepth-First SearchDesign | 47% | |
| 212 | Word Search II | — | Hard | ArrayStringBacktracking | 37% | |
| 213 | House Robber II | — | Medium | ArrayDynamic Programming | 43% | |
| 217 | Contains Duplicate | — | Easy | ArrayHash TableSorting | 63% | |