| LRU Cache ↗ | Medium | Hash Table, Linked List, Design | |
| Two Sum ↗ | Easy | Array, Hash Table | |
| Top K Frequent Elements ↗ | Medium | Array, Hash Table, Divide and Conquer | |
| Sliding Window Maximum ↗ | Hard | Array, Queue, Sliding Window | |
| Merge k Sorted Lists ↗ | Hard | Linked List, Divide and Conquer, Heap (Priority Queue) | |
| Minimum Window Substring ↗ | Hard | Hash Table, String, Sliding Window | |
| Diameter of Binary Tree ↗ | Easy | Tree, Depth-First Search, Binary Tree | |
| Merge Intervals ↗ | Medium | Array, Sorting | |
| Spiral Matrix ↗ | Medium | Array, Matrix, Simulation | |
| Container With Most Water ↗ | Medium | Array, Two Pointers, Greedy | |
| Valid Parentheses ↗ | Easy | String, Stack | |
| Number of Islands ↗ | Medium | Array, Depth-First Search, Breadth-First Search | |
| Koko Eating Bananas ↗ | Medium | Array, Binary Search | |
| Group Anagrams ↗ | Medium | Array, Hash Table, String | |
| Asteroid Collision ↗ | Medium | Array, Stack, Simulation | |
| LFU Cache ↗ | Hard | Hash Table, Linked List, Design | |
| Max Area of Island ↗ | Medium | Array, Depth-First Search, Breadth-First Search | |
| Sum Root to Leaf Numbers ↗ | Medium | Tree, Depth-First Search, Binary Tree | |
| Remove All Adjacent Duplicates in String II ↗ | Medium | String, Stack | |
| Open the Lock ↗ | Medium | Array, Hash Table, String | |
| 3Sum ↗ | Medium | Array, Two Pointers, Sorting | |
| Reverse Linked List ↗ | Easy | Linked List, Recursion | |
| Longest Consecutive Sequence ↗ | Medium | Array, Hash Table, Union-Find | |
| Min Stack ↗ | Medium | Stack, Design | |
| Minimum Absolute Difference ↗ | Easy | Array, Sorting | |
| Roman to Integer ↗ | Easy | Hash Table, Math, String | |
| Maximum Subarray ↗ | Medium | Array, Divide and Conquer, Dynamic Programming | |
| Valid Anagram ↗ | Easy | Hash Table, String, Sorting | |
| Rotting Oranges ↗ | Medium | Array, Breadth-First Search, Matrix | |
| Generate Parentheses ↗ | Medium | String, Dynamic Programming, Backtracking | |
| Decode String ↗ | Medium | String, Stack, Recursion | |
| Lowest Common Ancestor of a Binary Tree ↗ | Medium | Tree, Depth-First Search, Binary Tree | |
| Best Time to Buy and Sell Stock ↗ | Easy | Array, Dynamic Programming | |
| Longest Substring Without Repeating Characters ↗ | Medium | Hash Table, String, Sliding Window | |
| Trapping Rain Water ↗ | Hard | Array, Two Pointers, Dynamic Programming | |
| Longest Palindromic Substring ↗ | Medium | Two Pointers, String, Dynamic Programming | |
| Search in Rotated Sorted Array ↗ | Medium | Array, Binary Search | |
| Two Sum II - Input Array Is Sorted ↗ | Medium | Array, Two Pointers, Binary Search | |
| Meeting Rooms II ↗ | Medium | Array, Two Pointers, Greedy | |
| Course Schedule ↗ | Medium | Depth-First Search, Breadth-First Search, Graph Theory | |