| 1 | Two Sum | cpp, js, py, py | md | Easy | |
| 2 | Add Two Numbers | cpp, java | | Medium | |
| 3 | Longest Substring Without Repeating Characters | cpp, cpp, java | md, md | Medium | |
| 5 | Longest Palindromic Substring | java | md | Medium | |
| 6 | ZigZag Conversion | cpp, java, jpg | md, md | Medium | |
| 7 | Reverse Integer | java, py | | Easy | |
| 9 | Palindrome Number | cpp, py | | Easy | |
| 13 | Roman to Integer | cpp | | Easy | |
| 17 | Letter Combinations of a Phone Number | cpp | | Medium | |
| 20 | Valid Parentheses | py | | Easy | |
| 23 | Merge k Sorted Lists | java | md | Hard | |
| 34 | Find First and Last Position of Element in Sorted Array | java | md | Medium | |
| 37 | Sudoku Solver | java, py | | Hard | |
| 39 | Combination Sum | cpp, py | | Medium | |
| 42 | Trapping Rain Water | py, py | | Hard | |
| 46 | Permutations | cpp, py | | Medium | |
| 50 | Pow(x, n) | py | | Medium | |
| 51 | N-Queens | py | | Hard | |
| 52 | N-Queens II | py | | Hard | |
| 56 | Merge Intervals | js, py | md | Medium | |
| 60 | Permutation Sequence | c | | Hard | |
| 61 | Rotate List | java | | Medium | |
| 62 | Unique Paths | java | | Medium | |
| 63 | Unique Paths II | java | md | Medium | |
| 65 | Valid Number | java | | Hard | |
| 67 | Add Binary | java | | Easy | |
| 74 | Search a 2D Matrix | java | | Medium | |
| 75 | Sort Colors | js | | Medium | |
| 77 | Combinations | cpp | | Medium | |
| 78 | Subsets | cpp | | Medium | |
| 84 | Largest Rectangle in Histogram | py | | Hard | |
| 88 | Merge Sorted Array | js | | Easy | |
| 89 | Gray Code | java | | Medium | |
| 92 | Reverse Linked List II | cpp | | Medium | |
| 94 | Binary Tree Inorder Traversal | py | md | Medium | |
| 97 | Interleaving String | py | md | Hard | |
| 102 | Binary Tree Level Order Traversal | py | md | Medium | |
| 103 | Binary Tree Zigzag Level Order Traversal | py | md | Medium | |
| 104 | Maximum Depth of Binary Tree | cpp | | Easy | |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | cpp | | Medium | |
| 107 | Binary Tree Level Order Traversal II | py | md | Easy | |
| 108 | Convert Sorted Array to Binary Search Tree | cpp | | Easy | |
| 110 | Balanced Binary Tree | cpp | | Easy | |
| 111 | Minimum Depth of Binary Tree | py | md | Easy | |
| 125 | Valid Palindrome | c, py, py | md | Easy | |
| 130 | Surrounded Regions | py | md | Medium | |
| 144 | Binary Tree Preorder Traversal | py | md | Medium | |
| 145 | Binary Tree Postorder Traversal | py | md | Medium | |
| 147 | Insertion Sort List | js | | Medium | |
| 172 | Factorial Trailing Zeroes | py | | Easy | |
| 179 | Largest Number | js | | Medium | |
| 199 | Binary Tree Right Side View | py | md | Medium | |
| 200 | Number of Islands | cpp, py | md | Medium | |
| 202 | Happy Number | py | | Easy | |
| 206 | Reverse Linked List | cpp, cpp | md | Easy | |
| 207 | Course Schedule | cpp | | Medium | |
| 208 | Implement Trie (Prefix Tree) | cpp | | Medium | |
| 215 | Kth Largest Element in an Array | cpp | md | Medium | |
| 217 | Contains Duplicate | py | | Easy | |
| 226 | Invert Binary Tree | cpp, js | | Easy | |
| 231 | Power of Two | py | | Easy | |
| 242 | Valid Anagram | js | | Easy | |
| 297 | Serialize and Deserialize Binary Tree | cpp | | Hard | |
| 310 | Minimum Height Trees | cpp | | Medium | |
| 316 | Remove Duplicate Letters | cpp | | Medium | |
| 326 | Power of Three | py, py | md | Easy | |
| 332 | Reconstruct Itinerary | cpp | | Medium | |
| 342 | Power of Four | py | | Easy | |
| 344 | Reverse String | cpp, py, py | md | Easy | |
| 412 | Fizz Buzz | cpp, java, py | md | Easy | |
| 429 | N-ary Tree Level Order Traversal | py | md | Medium | |
| 454 | 4Sum II | py | md | Medium | |
| 515 | Find Largest Value in Each Tree Row | py | md | Medium | |
| 538 | Convert BST to Greater Tree | py | md | Medium | |
| 542 | 01 Matrix | py | md | Medium | |
| 543 | Diameter of Binary Tree | cpp | | Easy | |
| 547 | Number of Provinces | py | md | Medium | |
| 559 | Maximum Depth of N-ary Tree | py | md | Easy | |
| 561 | Array Partition I | js | | Easy | |
| 617 | Merge Two Binary Trees | cpp | | Easy | |
| 654 | Maximum Binary Tree | py | md | Medium | |
| 684 | Redundant Connection | py | md | Medium | |
| 687 | Longest Univalue Path | cpp | | Medium | |
| 701 | Insert into a Binary Search Tree | cpp, java, py | md | Medium | |
| 739 | Daily Temperatures | cpp | | Medium | |
| 743 | Network Delay Time | cpp, py | md | Medium | |
| 763 | Partition Labels | cpp, py | md | Medium | |
| 771 | Jewels and Stones | cpp | | Easy | |
| 783 | Minimum Distance Between BST Nodes | cpp | | Easy | |
| 787 | Cheapest Flights Within K Stops | cpp | | Medium | |
| 791 | Custom Sort String | py | md | Medium | |
| 797 | All Paths From Source to Target | cpp, py | md | Medium | |
| 807 | Max Increase to Keep City Skyline | py | md | Medium | |
| 827 | Making A Large Island | py | md | Hard | |
| 890 | Find and Replace Pattern | cpp, java, py | md | Medium | |
| 912 | Sort an Array | js | | Medium | |
| 921 | Minimum Add to Make Parentheses Valid | cpp, java, py | md | Medium | |
| 925 | Long Pressed Name | py | md | Easy | |
| 938 | Range Sum of BST | cpp | | Easy | |
| 945 | Minimum Increment to Make Array Unique | py | md | Medium | |
| 950 | Reveal Cards In Increasing Order | cpp, java, py | md | Medium | |
| 973 | K Closest Points to Origin | cpp | | Medium | |
| 990 | Satisfiability of Equality Equations | py | md | Medium | |
| 994 | Rotting Oranges | py | md | Medium | |
| 1008 | Construct Binary Search Tree from Preorder Traversal | cpp, py | md | Medium | |
| 1038 | Binary Search Tree to Greater Sum Tree | cpp, py | md | Medium | |
| 1091 | Shortest Path in Binary Matrix | py | md | Medium | |
| 1108 | Defanging an IP Address | py | md | Easy | |
| 1161 | Maximum Level Sum of a Binary Tree | py | md | Medium | |
| 1162 | As Far from Land as Possible | py | md | Medium | |
| 1261 | Find Elements in a Contaminated Binary Tree | cpp, java, py | md | Medium | |
| 1282 | Group the People Given the Group Size They Belong To | py | md | Medium | |
| 1288 | Remove Covered Intervals | py | md | Medium | |
| 1302 | Deepest Leaves Sum | py | md | Medium | |
| 1305 | All Elements in Two Binary Search Trees | cpp, py | md | Medium | |
| 1310 | XOR Queries of a Subarray | cpp | | Medium | |
| 1315 | Sum of Nodes with Even-Valued Grandparent | py | md | Medium | |
| 1325 | Delete Leaves With a Given Value | cpp, java, py | md | Medium | |
| 1329 | Sort the Matrix Diagonally | py | md | Medium | |
| 1334 | Find the City With the Smallest Number of Neighbors at a Threshold Distance | py | md | Medium | |
| 1342 | Number of Steps to Reduce a Number to Zero | cpp, java, py | md | Easy | |
| 1347 | Minimum Number of Steps to Make Two Strings Anagram | cpp, java, py | md | Medium | |
| 1365 | How Many Numbers Are Smaller Than the Current Number | cpp, java, py | md | Easy | |
| 1379 | Find a Corresponding Node of a Binary Tree in a Clone of That Tree | py | md | Medium | |
| 1381 | Design a Stack With Increment Operation | cpp, java, py | md | Medium | |
| 1382 | Balance a Binary Search Tree | cpp, py | md | Medium | |
| 1395 | Count Number of Teams | py | md | Medium | |
| 1409 | Queries on a Permutation With Key | py | md | Medium | |
| 1470 | Shuffle the Array | py | md | Easy | |
| 1480 | Running Sum of 1d Array | py | md | Easy | |
| 1512 | Number of Good Pairs | py | md | Easy | |
| 1528 | Shuffle String | cpp, java, py | md | Easy | |
| 1544 | Make The String Great | py | md | Easy | |
| 1551 | Minimum Operations to Make Array Equal | cpp, py | md | Medium | |
| 1557 | Minimum Number of Vertices to Reach All Nodes | cpp, java, py | md | Medium | |
| 1561 | Maximum Number of Coins You Can Get | cpp, py | md | Medium | |
| 1603 | Design Parking System | cpp, java, py | md | Easy | |
| 1630 | Arithmetic Subarrays | cpp, py | md | Medium | |
| 1637 | Widest Vertical Area Between Two Points Containing No Points | py | md | Medium | |
| 1641 | Count Sorted Vowel Strings | cpp, py | md | Medium | |
| 1669 | Merge In Between Linked Lists | cpp, py | md | Medium | |
| 1672 | Richest Customer Wealth | py | md | Easy | |
| 1689 | Partitioning Into Minimum Number Of Deci-Binary Numbers | py | md | Medium | |
| 1720 | Decode XORed Array | cpp, java, py | md | Easy | |
| 1725 | Number Of Rectangles That Can Form The Largest Square | py | md | Easy | |