| LRU Cache ↗ | Medium | Hash Table, Linked List, Design | |
| Longest Increasing Subsequence ↗ | Medium | Array, Binary Search, Dynamic Programming | |
| Course Schedule II ↗ | Medium | Depth-First Search, Breadth-First Search, Graph Theory | |
| Trapping Rain Water ↗ | Hard | Array, Two Pointers, Dynamic Programming | |
| Number of Islands ↗ | Medium | Array, Depth-First Search, Breadth-First Search | |
| Longest Palindromic Substring ↗ | Medium | Two Pointers, String, Dynamic Programming | |
| N-Queens ↗ | Hard | Array, Backtracking | |
| Minimum Window Substring ↗ | Hard | Hash Table, String, Sliding Window | |
| Course Schedule ↗ | Medium | Depth-First Search, Breadth-First Search, Graph Theory | |
| 3Sum ↗ | Medium | Array, Two Pointers, Sorting | |
| Sqrt(x) ↗ | Easy | Math, Binary Search | |
| Coin Change ↗ | Medium | Array, Dynamic Programming, Breadth-First Search | |
| Longest Consecutive Sequence ↗ | Medium | Array, Hash Table, Union-Find | |
| Merge k Sorted Lists ↗ | Hard | Linked List, Divide and Conquer, Heap (Priority Queue) | |
| Making A Large Island ↗ | Hard | Array, Depth-First Search, Breadth-First Search | |
| Text Justification ↗ | Hard | Array, String, Simulation | |
| Valid Parentheses ↗ | Easy | String, Stack | |
| House Robber ↗ | Medium | Array, Dynamic Programming | |
| Basic Calculator II ↗ | Medium | Math, String, Stack | |
| Basic Calculator III ↗ | Hard | Math, String, Stack | |
| Snapshot Array ↗ | Medium | Array, Hash Table, Binary Search | |
| Two Sum ↗ | Easy | Array, Hash Table | |
| Word Ladder ↗ | Hard | Hash Table, String, Breadth-First Search | |
| Generate Parentheses ↗ | Medium | String, Dynamic Programming, Backtracking | |
| Sort Colors ↗ | Medium | Array, Two Pointers, Sorting | |
| Insert Delete GetRandom O(1) ↗ | Medium | Array, Hash Table, Math | |
| Longest Increasing Path in a Matrix ↗ | Hard | Array, Dynamic Programming, Depth-First Search | |
| Valid Parenthesis String ↗ | Medium | String, Dynamic Programming, Stack | |
| Max Area of Island ↗ | Medium | Array, Depth-First Search, Breadth-First Search | |
| Decode String ↗ | Medium | String, Stack, Recursion | |
| Meeting Rooms II ↗ | Medium | Array, Two Pointers, Greedy | |
| Subsets ↗ | Medium | Array, Backtracking, Bit Manipulation | |
| Cheapest Flights Within K Stops ↗ | Medium | Dynamic Programming, Depth-First Search, Breadth-First Search | |
| Path Sum III ↗ | Medium | Tree, Depth-First Search, Binary Tree | |
| Gas Station ↗ | Medium | Array, Greedy | |
| Possible Bipartition ↗ | Medium | Depth-First Search, Breadth-First Search, Union-Find | |
| Daily Temperatures ↗ | Medium | Array, Stack, Monotonic Stack | |
| Construct Binary Tree from Preorder and Inorder Traversal ↗ | Medium | Array, Hash Table, Divide and Conquer | |
| Add Strings ↗ | Easy | Math, String, Simulation | |
| Word Search II ↗ | Hard | Array, String, Backtracking | |