| 1. Two Sum |
Easy |
| 2. Add Two Numbers |
Medium |
| 3. Longest Substring Without Repeating Characters (Array Reduce solution) |
Medium |
| 3. Longest Substring Without Repeating Characters |
Medium |
| 4. Median of Two Sorted Arrays |
Hard |
| 5. Longest Palindromic Substring |
Medium |
| 6. Zigzag Conversion |
Medium |
| 7. Reverse Integer |
Medium |
| 8. String to Integer (atoi) |
Medium |
| 10. Regular Expression Matching |
Hard |
| 11. Container With Most Water |
Medium |
| 12. Integer to Roman |
Medium |
| 13. Roman to Integer |
Easy |
| 15. 3Sum |
Medium |
| 16. 3Sum Closest |
Medium |
| 17. Letter Combinations of a Phone Number |
Medium |
| 18. 4Sum |
Medium |
| 19. Remove Nth Node From End of List |
Medium |
| 20. Valid Parentheses |
Easy |
| 22. Generate Parentheses |
Medium |
| 22. Generate Parentheses (With comments) |
Medium |
| 23. Merge k Sorted Lists |
Hard |
| 24. Swap Nodes in Pairs |
Medium |
| 25. Reverse Nodes in k-Group |
Hard |
| 26. Remove Duplicates from Sorted Array |
Easy |
| 31. Next Permutation |
Medium |
| 38. Count and Say |
Medium |
| 42. Trapping Rain Water (2 Pointer solution) |
Hard |
| 44. Wildcard Matching |
Hard |
| 46. Permutations |
Medium |
| 48. Rotate Image |
Medium |
| 49. Group Anagrams |
Medium |
| 50. Pow(x, n) |
Medium |
| 54. Spiral Matrix |
Medium |
| 55. Jump Game |
Medium |
| 66. Plus One |
Easy |
| 79. Word Search |
Medium |
| 94. Binary Tree Inorder Traversal |
Easy |
| 98. Validate Binary Search Tree |
Medium |
| 99. Recover Binary Search Tree |
Medium |
| 108. Conert Sorted Array to Binary Search Tree |
Easy |
| 113. Path Sum II |
Medium |
| 158. Read N Characters Given read4 II - Call Multiple Times |
Hard |
| 200. Number of Islands (DFS solution) |
Medium |
| 218. The Skyline Problem |
Hard |
| 219. Contains Duplicate II |
Easy |
| 226. Invert Binary Tree |
Easy |
| 235. Lowest Common Ancestor of a Binary Search Tree |
Easy |
| 300. Longest Increasing Subsequence |
Medium |
| 326. Power of Three |
Easy |
| 336. Palindrome Pairs (brute force) |
Hard |
| 336. Palindrome Pairs (Map Solution) |
Hard |
| 342. Power of Four |
Easy |
| 350. Intersection of Two Arrays II |
Easy |
| 363. Max Sum of Rectangle No Larger Than K |
Hard |
| 377. Combination Sum IV |
Medium |
| 378. Kth Smallest Element in a Sorted Matrix |
Medium |
| 383. Ransom Note |
Easy |
| 387. First Unique Character in a String |
Easy |
| 412. Fizz Buzz |
Easy |
| 417. Pacific Atlantic Water Flow |
Medium |
| 458. Poor Pigs |
Hard |
| 482. License Key Formatting |
Easy |
| 557. Reverse Words in a String III |
Easy |
| 622. Design Circular Queue |
Medium |
| 637. Average of Levels in Binary Tree |
Easy |
| 658. Find K Closest Elements |
Medium |
| 659. Split Array into Consecutive Subsequences |
Medium |
| 777. Swap Adjacent in LR String |
Medium |
| 804. Unique Morse Code Words |
Easy |
| 814. Binary Tree Pruning |
Medium |
| 876. Middle of the Linked List |
Easy |
| 904. Fruit Into Baskets |
Medium |
| 929. Unique Email Addresses |
Easy |
| 985. Sum of Even Numbers After Queries |
Medium |
| 987. Vertical Order Traversal of a Binary Tree |
Hard |
| 1329. Sort the Matrix Diagonally |
Medium |
| 1338. Reduce Array Size to The Half |
Medium |
| 1342. Number of Steps to Reduce a Number to Zero |
Easy |
| 1465. Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts |
Medium |
| 1578. Minimum Time to Make Rope Colorful |
Medium |
| 1647. Minimum Deletions to Make Character Frequencies Unique |
Medium |
| 1672. Richest Customer Wealth |
Easy |
| 1680. Concatenation of Consecutive Binary Numbers |
Medium |
| 1680. Concatenation of Consecutive Binary Numbers - with Shift Operator |
Medium |
| 1689. Partitioning Into Minimum Number Of Deci-Binary Numbers |
Medium |
| 2007. Find Original Array From Doubled Array |
Medium |