| Number of Islands ↗ | Medium | Array, Depth-First Search, Breadth-First Search | |
| LRU Cache ↗ | Medium | Hash Table, Linked List, Design | |
| Valid Parentheses ↗ | Easy | String, Stack | |
| Search in Rotated Sorted Array ↗ | Medium | Array, Binary Search | |
| Middle of the Linked List ↗ | Easy | Linked List, Two Pointers | |
| Count Elements With Maximum Frequency ↗ | Easy | Array, Hash Table, Counting | |
| Word Break ↗ | Medium | Array, Hash Table, String | |
| Coin Change ↗ | Medium | Array, Dynamic Programming, Breadth-First Search | |
| Longest Palindromic Substring ↗ | Medium | Two Pointers, String, Dynamic Programming | |
| Container With Most Water ↗ | Medium | Array, Two Pointers, Greedy | |
| Longest Consecutive Sequence ↗ | Medium | Array, Hash Table, Union-Find | |
| Longest Increasing Subsequence ↗ | Medium | Array, Binary Search, Dynamic Programming | |
| Combination Sum ↗ | Medium | Array, Backtracking | |
| Two Sum ↗ | Easy | Array, Hash Table | |
| 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 | |
| 3Sum ↗ | Medium | Array, Two Pointers, Sorting | |
| Merge Intervals ↗ | Medium | Array, Sorting | |
| Subarray Sum Equals K ↗ | Medium | Array, Hash Table, Prefix Sum | |
| Group Anagrams ↗ | Medium | Array, Hash Table, String | |
| Move Zeroes ↗ | Easy | Array, Two Pointers | |
| Generate Parentheses ↗ | Medium | String, Dynamic Programming, Backtracking | |
| Sort Colors ↗ | Medium | Array, Two Pointers, Sorting | |
| Course Schedule ↗ | Medium | Depth-First Search, Breadth-First Search, Graph Theory | |
| Sliding Window Maximum ↗ | Hard | Array, Queue, Sliding Window | |
| Zigzag Conversion ↗ | Medium | String | |
| Permutation in String ↗ | Medium | Hash Table, Two Pointers, String | |
| LFU Cache ↗ | Hard | Hash Table, Linked List, Design | |
| Subarray Product Less Than K ↗ | Medium | Array, Binary Search, Sliding Window | |
| Median of Two Sorted Arrays ↗ | Hard | Array, Binary Search, Divide and Conquer | |
| Spiral Matrix ↗ | Medium | Array, Matrix, Simulation | |
| Kth Largest Element in an Array ↗ | Medium | Array, Divide and Conquer, Sorting | |
| First Unique Character in a String ↗ | Easy | Hash Table, String, Queue | |
| Find Median from Data Stream ↗ | Hard | Two Pointers, Design, Sorting | |
| Binary Tree Zigzag Level Order Traversal ↗ | Medium | Tree, Breadth-First Search, Binary Tree | |
| Longest Common Prefix ↗ | Easy | Array, String, Trie | |
| Maximum Subarray ↗ | Medium | Array, Divide and Conquer, Dynamic Programming | |
| Top K Frequent Elements ↗ | Medium | Array, Hash Table, Divide and Conquer | |
| Add Binary ↗ | Easy | Math, String, Bit Manipulation | |