| ID | Difficulty | Problem | Topics | Link |
|---|---|---|---|---|
| 0001 | Easy | Two Sum | Array, HashMap | solution |
| 0002 | Medium | Add Two numbers | LinkedList, Recursion | solution |
| 0003 | Medium | Longest Substring Without Repeating Characters | Hash Table, String, Sliding Window | solution |
| 0004 | Hard | Median of Two Sorted Arrays | Array, Binary Search, Divide and Conquer | solution |
| 0011 | Medium | Container With Most Water | Array, Two Pointers, Greedy | solution |
| 0015 | Medium | Three sum | Array, Two Pointers, Sorting | solution |
| 0019 | Medium | Remove Nth Node From End Of List | Linked List, Two Pointers | solution |
| 0021 | Easy | Merge Two Sorted Lists | Linked List, Recursion | solution |
| 0022 | Medium | Generate Parentheses | String, Dynamic Programming, Backtracking | solution |
| 0023 | Hard | Merge K sorted Lists | Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort | solution |
| 0025 | Hard | Reverse Nodes in k-Group | Linked List, Recursion | solution |
| 0033 | Medium | Search in Rotated Sorted Array | Array, Binary Search | solution |
| 0036 | Medium | Valid Sudoku | Array, HashTable, Matrix | solution |
| 0042 | Hard | Trapping Rain Water | Array, Two Pointers, Dynamic Programming, Stack | solution |
| 0049 | Medium | Group Anagrams | Array, HashTable, String, Sorting | solution |
| 0074 | Medium | Search a 2D Matrix | Array, Binary Search, Matrix | solution |
| 0076 | Hard | Minimum Window Substring | Hash Table, String, Sliding Window | solution |
| 0078 | Medium | Subsets | Array, Backtracking, Bit Manipulation | solution |
| 0084 | Hard | Largest Rectangle in Histogram | Array, Stack, Monotonic Stack | solution |
| 0098 | Medium | Validate Binary Search Tree | Tree, Depth-First Search, Binary Search Tree, Binary Tree | solution |
| 0100 | Easy | Same Tree | Tree, Depth-First Search, Breadth-First Search, Binary Tree | solution |
| 0102 | Medium | Binary Tree Level Order Traversal | Tree, Breadth-First Search, Binary Tree | solution |
| 0104 | Easy | Maximum Depth of Binary Tree | Tree, Depth-First Search, Breadth-First Search, Binary Tree | solution |
| 0105 | Medium | Construct Binary Tree from Preorder and Inorder Traversal | Array, Hash Table, Divide and Conquer, Tree, Binary Tree | solution |
| 0110 | Easy | Balanced Binary Tree | Tree, Depth-First Search, Binary Tree | solution |
| 0111 | Easy | Minimum Depth of Binary Tree | Tree, Depth-First Search, Breadth-First Search, Binary Tree | solution |
| 0121 | Easy | Best Time to Buy and Sell Stock | Array | solution |
| 0124 | Hard | Binary Tree Maximum Path Sum | Dynamic Programming, Tree, Depth-First Search, Binary Tree | solution |
| 0125 | Easy | Valid Palindrome | String, Two Pointers | solution |
| 0128 | Medium | Longest Consecutive Sequence | Array, HashSet | solution |
| 0138 | Medium | Copy List with Random Pointer | Linked List, Hash Table | solution |
| 0141 | Easy | Linked List Cycle | Hash Table, Linked List, Two Pointers | solution |
| 0143 | Medium | Reorder List | Linked List, Two Pointers, Stack, Recursion | solution |
| 0146 | Medium | LRU Cache | Hash Table, Design, Linked List, Doubly-Linked List | solution |
| 0150 | Medium | Evaluate Reverse Polish Notation | Array, Math, Stack | solution |
| 0153 | Medium | Find Minimum in Rotated Sorted Array | Array, Binary Search | solution |
| 0155 | Medium | Min Stack | Stack, Design | solution |
| 0167 | Medium | Two Sum II - Input Array Is Sorted | Array, Two Pointers | solution |
| 0169 | Easy | Majority Element | Array, HashTable, Counting | solution |
| 0199 | Medium | Binary Tree Right Side View | Tree, Depth-First Search, Breadth-First Search, Binary Tree | solution |
| 0206 | Easy | Reverse Linked List | Linked List, Recursion | solution |
| 0208 | Medium | Implement Trie (Prefix Tree) | Hash Table, String, Design, Trie | solution |
| 0211 | Medium | Design Add and Search Words Data Structure | String, Depth-First Search, Design, Trie | solution |
| 0212 | Hard | Word Search II | Array, String, Backtracking, Trie, Matrix | solution |
| 0215 | Medium | Kth Largest Element in an Array | Array, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect | solution |
| 0217 | Easy | Contains Duplicate | Array | solution |
| 0219 | Easy | Contains Duplicate II | Array | solution |
| 0226 | Easy | Invert Binary Tree | Tree, Depth-First Search, Breadth-First Search, Binary Tree | solution |
| 0230 | Medium | Kth Smallest Element in a BST | Tree, Depth-First Search, Binary Search Tree, Binary Tree | solution |
| 0236 | Medium | Lowest Common Ancestor of a Binary Tree | Tree, Depth-First Search, Binary Tree | solution |
| 0238 | Medium | Product of Array Except Self | Array | solution |
| 0239 | Hard | Sliding Window Maximum | Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue | solution |
| 0242 | Easy | Valid Anagram | String, HashTable | solution |
| 0287 | Medium | Find the Duplicate Number | Array, Two Pointers, Binary Search, Bit Manipulation | solution |
| 0297 | Hard | Serialize and Deserialize Binary Tree | String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree | solution |
| 0347 | Medium | Top K Frequent Elements | Array, HashMap, Bucket Sort | Solution |
| 0392 | Easy | Is Subsequence | Two Pointers, String, Dynamic Programming | solution |
| 0424 | Medium | Longest Repeating Character Replacement | HashTable, String, Sliding Windows | solution |
| 0543 | Easy | Diameter of Binary Tree | Tree, Depth-First Search, Binary Tree | solution |
| 0567 | Medium | Permutation in String | Hash Table, Two Pointers, String, Sliding Window | solution |
| 0572 | Easy | Subtree of Another Tree | Tree, Depth-First Search, String Matching, Binary Tree, Hash Function | solution |
| 0703 | Easy | Kth Largest Element in a Stream | Tree, Design, Binary Search Tree, Heap (Priority Queue), Binary Tree, Data Stream | solution |
| 0704 | Easy | Binary Search | Array, Binary Search | solution |
| 0739 | Medium | Daily Temperatures | Array, Stack, Monotonic Stack | solution |
| 0853 | Medium | Car Fleet | Array, Stack, Sorting, Monotonic Stack | solution |
| 0875 | Medium | Koko Eating Bananas | Array, Binary Search | solution |
| 0973 | Medium | K Closest Points to Origin | Array, Math, Divide and Conquer, Geometry, Sorting, Heap (Priority Queue), Quickselect | solution |
| 0981 | Medium | Time Based Key-Value Store | Hash Table, String, Binary Search, Design | solution |
| 1046 | Easy | Last Stone Weight | Array, Heap (Priority Queue) | solution |
| 1448 | Medium | Count Good Nodes in Binary Tree | Tree, Depth-First Search, Breadth-First Search, Binary Tree | solution |
| 1768 | Easy | Merge Strings Alternately | Two Pointers, String | solution |
