| Contains Duplicate | Arrays | Easy |
| Best Time to Buy and Sell Stock | Arrays | Easy |
| Two Sum | Arrays | Easy |
| Valid Parentheses | Arrays | Easy |
| Valid Palindrome | String | Easy |
| Valid Anagram | String | Easy |
| Detect Cycle in a Linked List | Linked List | Easy |
| Merge Two Sorted Lists | Linked List | Easy |
| Reverse a Linked List | Linked List | Easy |
| Number of 1 Bits | Binary | Easy |
| Missing Number | Binary | Easy |
| Reverse Bits | Binary | Easy |
| Counting Bits | Binary | Easy |
| Subtree of Another Tree | Tree | Easy |
| Maximum Depth of Binary Tree | Tree | Easy |
| Invert/Flip Binary Tree | Tree | Easy |
| Same Tree | Tree | Easy |
| Meeting Rooms (Leetcode Premium) | Interval | Easy |
| Climbing Stairs | Dynamic Programming | Easy |
| Maximum Subarray | Arrays | Medium |
| Container With Most Water | Arrays | Medium |
| Product of Array Except Self | Arrays | Medium |
| Search in Rotated Sorted Array | Arrays | Medium |
| Maximum Product Subarray | Arrays | Medium |
| Find Minimum in Rotated Sorted Array | Arrays | Medium |
| 3Sum | Arrays | Medium |
| Group Anagrams | String | Medium |
| Longest Palindromic Substring | String | Medium |
| Palindromic Substrings | String | Medium |
| Longest Repeating Character Replacement | String | Medium |
| Encode and Decode Strings (Leetcode Premium) | String | Medium |
| Longest Substring Without Repeating Characters | String | Medium |
| Remove Nth Node From End Of List | Linked List | Medium |
| Reorder List | Linked List | Medium |
| Sum of Two Integers | Binary | Medium |
| Rotate Image | Matrix | Medium |
| Set Matrix Zeroes | Matrix | Medium |
| Word Search | Matrix | Medium |
| Spiral Matrix | Matrix | Medium |
| Lowest Common Ancestor of BST | Tree | Medium |
| Kth Smallest Element in a BST | Tree | Medium |
| Construct Binary Tree from Preorder and Inorder Traversal | Tree | Medium |
| Validate Binary Search Tree | Tree | Medium |
| Add and Search Word | Tree | Medium |
| Implement Trie (Prefix Tree) | Tree | Medium |
| Binary Tree Level Order Traversal | Tree | Medium |
| Merge Intervals | Interval | Medium |
| Meeting Rooms II (Leetcode Premium) | Interval | Medium |
| Insert Interval | Interval | Medium |
| Non-overlapping Intervals | Interval | Medium |
| Top K Frequent Elements | Heap | Medium |
| Course Schedule | Graph | Medium |
| Pacific Atlantic Water Flow | Graph | Medium |
| Number of Connected Components in an Undirected Graph (Leetcode Premium) | Graph | Medium |
| Graph Valid Tree (Leetcode Premium) | Graph | Medium |
| Clone Graph | Graph | Medium |
| Number of Islands | Graph | Medium |
| Longest Consecutive Sequence | Graph | Medium |
| House Robber | Dynamic Programming | Medium |
| Unique Paths | Dynamic Programming | Medium |
| Longest Increasing Subsequence | Dynamic Programming | Medium |
| House Robber II | Dynamic Programming | Medium |
| Decode Ways | Dynamic Programming | Medium |
| Jump Game | Dynamic Programming | Medium |
| Word Break Problem | Dynamic Programming | Medium |
| Longest Common Subsequence | Dynamic Programming | Medium |
| Combination Sum | Dynamic Programming | Medium |
| Coin Change | Dynamic Programming | Medium |
| Minimum Window Substring | String | Hard |
| Binary Tree Maximum Path Sum | Tree | Hard |
| Serialize and Deserialize Binary Tree | Tree | Hard |
| Word Search II | Tree | Hard |
| Find Median from Data Stream | Heap | Hard |
| Merge K Sorted Lists | Heap | Hard |
| Alien Dictionary (Leetcode Premium) | Graph | Hard |