LeetCode problems' solutions with explanation
| # | Title | Difficulty | Related Topics | Solution |
|---|---|---|---|---|
| 1 | Two Sum | 🟢 | Array, Hash Table | Java |
| 2 | Add Two Numbers | 🟡 | Linked List, Math, Recursion | Java |
| 4 | Median of Two Sorted Arrays | 🔴 | Array, Binary Search, Devide and Conquer | Java |
| 7 | Reverse Integer | 🟡 | Math | Java |
| 9 | Palindrome Number | 🟢 | Math | Java |
| 13 | Roman to Integer | 🟢 | Hash Table, Math, String | Java |
| 20 | Valid Parentheses | 🟢 | String, Stack | Java |
| 21 | Merge Two Sorted Lists | 🟢 | Linked List, Recursion | Java |
| 26 | Remove Duplicates from Sorted Array | 🟢 | Array, Two Pointers | Java |
| 70 | Climbing Stairs | 🟢 | Math, Dynamic Programming, Memoization | Java |
| 121 | Best Time to Buy and Sell Stock | 🟢 | Array, Dynamic Programming | Java |
| 206 | Reverse Linked List | 🟢 | Linked List, Recursion | Java |
| 278 | First Bad Version | 🟢 | Binary Search, Interactive | Java |
| 383 | Ransom Note | 🟢 | Hash Table, String, Counting | Java |
| 392 | Is Subsequence | 🟢 | Two Pointers, String, Dynamic Programming | Java |
| 409 | Longest Palindrome | 🟢 | Hash Table, String, Greedy | Java |
| 412 | Fizz Buzz | 🟢 | Math, String, Simulation | Java |
| 509 | Fibonacci Number | 🟢 | Math, Dynamic Programming, Recursion, Memoization | Java |
| 589 | N-ary Tree Preorder Traversal | 🟢 | Stack, Tree, Depth-First-Search | Java |
| 704 | Binary Search | 🟢 | Array, Binary Search | Java |
| 724 | Find Pivot Index | 🟢 | Array, Prefix Sum | Java |
| 733 | Flood Fill | 🟢 | Array, Depth-First-Search, Breadth-First-Search, Matrix | Java |
| 876 | Middle of the Linked List | 🟢 | Linked List, Two Pointers | Java |
| 1342 | Number of Steps to Reduce a Number to Zero | 🟢 | Math, Bit Manipulation | Java |
| 1480 | Running Sum of 1d Array | 🟢 | Array, Prefix Sum | Java |
| 1672 | Richest Customer Wealth | 🟢 | Array, Matrix | Java |