My solutions for LeetCode
I will put my solutions (of course, the accepted ones) of Leetcode Problems in this repo. Every problem will be done in Java.
Problems
| ID | Problem | Relative Topic |
|---|---|---|
| 001 | Two Sum | Brutal Force, Hash Table |
| 002 | Add Two Numbers | Integer Addition |
| 003 | Longest Substring Without Repeating Characters | Double Pointers |
| 004 | Median of Two Sorted Arrays | Merge Sort |
| 005 | Longest Palindromic Substring | Dynamic Programming |
| 006 | ZigZag Conversion | Brutal Force |
| 007 | Reverse Integer | Brutal Force |
| 008 | String to Integer (atoi) | Brutal Force |
| 009 | Palindrome Number | Brutal Force (Reverse Half) |
| 010 | Regular Expression Matching | Brutal Force |
| 011 | Container With Most Water | Greedy |
| 012 | Integer to Roman | Brutal Force |
| 013 | Roman to Integer | Brutal Force |
| 014 | Longest Common Prefix | Brutal Force, Divide and Conquer (Not Implemented) |
| 015 | 3Sum | Binary Search |
| 016 | 3Sum Closest | Binary Search |
| 017 | Letter Combinations of a Phone Number | Backtracking (DFS) |
| 018 | 4Sum | Binary Search |
| 019 | Remove Nth Node From End of List | Double Pointers |
| 020 | Valid Parentheses | Stack |
| 021 | Merge Two Sorted Lists | Merge Sort |
| 022 | Generate Parentheses | Dynamic Programming |
| 023 | Merge k Sorted Lists | Merge Sort (Using Priority Queue) |
| 024 | Swap Nodes in Pairs | Double Pointers, Stack |
| 025 | Reverse Nodes in k-Group | Stack |
| 026 | Remove Duplicates from Sorted Array | Brutal Force |
| 027 | Remove Element | Brutal Force |
| 028 | Implement strStr() | Brutal Force |
| 029 | Divide Two Integers | Binary Long Division |
| 030 | Substring with Concatenation of All Words | Hash Table |
| 031 | Next Permutation | Single Pass Approach |
| 032 | Longest Valid Parentheses | Stack, Dynamic Programming |
| 033 | Search in Rotated Sorted Array | Binary Search |
| 034 | Search for a Range | Binary Search |
| 035 | Search Insert Position | Brutal Force, Binary Search |
| 036 | Valid Sudoku | Brutal Force, Hash Table |
| 037 | Sudoku Solver | Backtracking (DFS) |
| 038 | Count and Say | Brutal Force |
| 039 | Combination Sum | Backtracking (DFS) |
| 040 | Combination Sum II | Backtracking (DFS) |
| 041 | First Missing Positive | Bucket Sort |
| 043 | Multiply Strings | Integer Long Multiplication |
| 044 | Wildcard Matching | Brutal Force, Dynamic Programming |
| 046 | Permutations | Backtracking (DFS) |
| 047 | Permutations II | Backtracking (DFS) |
| 048 | Rotate Image | Brutal Force |
| 049 | Group Anagrams | Hash Table |
| 050 | Pow(x, n) | Divide and Conquer |
| 051 | N-Queens | Backtracking (DFS) |
| 052 | N-Queens-II | Backtracking (DFS) |
| 053 | Maximum Subarray | Dynamic Programming |
| 056 | Merge Intervals | Brutal Force |
| 057 | Insert Interval | Brutal Force |
| 058 | Length of Last Word | Brutal Force |
| 060 | Permutation Sequence | Brutal Force (Reuse 031) |
| 061 | Rotate List | Linked List |
| 062 | Unique Paths | Dynamic Programming |
| 063 | Unique Paths II | Dynamic Programming |
| 064 | Minimum Path Sum | Dynamic Programming |
| 065 | Valid Number | Brutal Force |
| 066 | Plus One | Integer Addition |
| 067 | Add Binary | Binary Integer Addition |
| 068 | Text Justification | Brutal Force |
| 069 | Sqrt(x) | Brutal Force, Newton Method |
| 070 | Climbing Stairs | Dynamic Programming (Fibonacci) |
| 071 | Simplify Path | Stack |
| 072 | Edit Distance | Dynamic Programming |
| 073 | Set Matrix Zeroes | Hash Table |
| 074 | Search a 2D Matrix | Binary Search |
| 075 | Sort Colors | Hash Table |
| 076 | Minimum Window Substring | Hash Table |
| 077 | Combinations | Backtracking (DFS) |
| 078 | Subsets | Backtracking (DFS) |
| 079 | Word Search | Backtracking (DFS) |
| 080 | Remove Duplicates from Sorted Array II | Brutal Force |
| 082 | Remove Duplicates from Sorted List II | Linked List |
| 083 | Remove Duplicates from Sorted List | Linked List |
| 085 | Maximal Rectangle | Dynamic Programming |
| 086 | Partition List | Linked List |
| 087 | Scramble String | Dynamic Programming |
| 089 | Gray Code | Bit Manipulation, Brutal Force |
| 090 | Subsets II | Backtracking (DFS) |
| 091 | Decode Ways | Backtracking, Dynamic Programming |
| 092 | Reverse Linked List II | Stack |
| 093 | Restore IP Addresses | Backtracking (DFS) |
| 094 | Binary Tree Inorder Traversal | Binary Tree Traversal |
| 095 | Unique Binary Search Trees II | |
| 096 | Unique Binary Search Trees | Dynamic Programming |
| 098 | Validate Binary Search Tree | Binary Tree Traversal |
| 099 | Recover Binary Search Tree | Binary Tree Traversal |
| 100 | Same Tree | Binary Tree |
| 101 | Symmetric Tree | Binary Tree |
| 102 | Binary Tree Level Order Traversal | Binary Tree Traversal |
| 103 | Binary Tree Zigzag Level Order Traversal | Binary Tree Traversal |
| 104 | Maximum Depth of Binary Tree | Binary Tree |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | Binary Tree Traversal |
| 106 | Construct Binary Tree from Inorder and Postorder Traversal | Binary Tree Traversal |
| 107 | Binary Tree Level Order Traversal II | Binary Tree Traversal |
| 108 | Convert Sorted Array to Binary Search Tree | Binary Tree |
| 109 | Convert Sorted List to Binary Search Tree | Binary Tree & Linked List |
| 110 | Balanced Binary Tree | Binary Tree Traversal |
| 111 | Minimum Depth of Binary Tree | Binary Tree Traversal |
| 112 | Path Sum | Binary Tree |
| 113 | Path Sum II | Binary Tree & Backtracking (DFS) |
| 114 | Flatten Binary Tree to Linked List | Binary Tree Traversal |
| 115 | Distinct Subsequences | Dynamic Programming |
| 116 | Populating Next Right Pointers in Each Node | Binary Tree & Linked List |
| 117 | Populating Next Right Pointers in Each Node II | Binary Tree & Linked List |
| 118 | Pascal's Triangle | Brutal Force |
| 119 | Pascal's Triangle II | Brutal Force |
| 120 | Triangle | Dynamic Programming |
| 121 | Best Time to Buy and Sell Stock | Dynamic Programming |
| 122 | Best Time to Buy and Sell Stock II | Greedy |
| 123 | Best Time to Buy and Sell Stock III | Dynamic Programming |
| 125 | Valid Palindrome | String (Palindrome) |
| 126 | Word Ladder II | BFS & DFS, Graph (optimal path) |
| 127 | Word Ladder | BFS |
| 128 | Longest Consecutive Sequence | Sorting, Hash Table |
| 129 | Sum Root to Leaf Numbers | Binary Tree Traversal (DFS) |
| 130 | Surrounded Regions | DFS |
| 133 | Clone Graph | DFS |
| 136 | Single Number | Hash Table, Bit Manipulation |
| 137 | Single Number II | Hash Table, Bit Manipulation |
| 138 | Copy List with Random Pointer | Linked List |
| 139 | Word Break | BFS, Dynamic Programming |
| 140 | Word Break II | cached DFS |
| 141 | Linked List Cycle | Double Pointers, Hash Table |
| 142 | Linked List Cycle II | Double Pointers |
| 143 | Reorder List | Linked List |
| 144 | Binary Tree Preorder Traversal | Binary Tree Traversal |
| 145 | Binary Tree Postorder Traversal | Binary Tree Traversal |
| 148 | Sort List | Merge Sort |
| 149 | Max Points on a Line | Hash table |
| 160 | Intersection of Two Linked Lists | Hash Table, Linked List |
| 167 | Two Sum II - Input array is sorted | Binary Search |
| 168 | Excel Sheet Column Title | Math |
| 169 | Majority Element | Hash Map |
| 171 | Excel Sheet Column Number | Math |
| 172 | Factorial Trailing Zeroes | Math |
| 173 | Binary Search Tree Iterator | Binary Tree Inorder Traversal |
| 174 | Dungeon Game | Dynamic Programming |
| 179 | Largest Number | Sort |
| 188 | Best Time to Buy and Sell Stock IV | Dynamic Programming |
| 189 | Rotate Array | Arrays |
| 190 | Reverse Bits | Bit Manipulation |
| 191 | Number of 1 Bits | Bit Manipulation |
| 198 | House Robber | Dynamic Programming |
| 200 | Number of Islands | DFS, BFS |
| 201 | Bitwise AND of Numbers Range | Bit Manipulation |
| 202 | Happy Number | Hash Table |
| 203 | Remove Linked List Elements | Linked List |
| 204 | Count Primes | Sheive Method |
| 205 | Isomorphic Strings | Hash Table |
| 206 | Reverse Linked List | Linked List, Stack |
| 207 | Course Schedule | Graph Topological Sort (DFS & BFS), Cyclic Path Detection |
| 208 | Implement Trie (Prefix Tree) | Trie |
| 212 | Word Search II | Backtracking (DFS), Trie |
| 215 | Kth Largest Element in an Array | Heap Sort |
| 237 | Delete Node in a Linked List | Linked List |
| 221 | Maximal Square | Dynamic Programming |
| 225 | Implement Stack using Queues | Stack, Queue |
| 230 | Kth Smallest Element in a BST | Binary Search Tree |
| 231 | Power of Two | Bit Manipulation |
| 232 | Implement Queue using Stacks | Queue, Stack |
| 233 | Number of Digit One | Math |
| 234 | Palindrome Linked List | Linked List |
| 235 | Lowest Common Ancestor of a Binary Search Tree | Binary Tree |
| 236 | Lowest Common Ancestor of a Binary Tree | Binary Tree |
| 297 | Serialize and Deserialize Binary Tree | BFS |
| 230 | Kth Smallest Element in a BST | Binary Tree Traversal |
| 231 | Power of Two | Bit Manipulation |
| 232 | Implement Queue using Stacks | Stack, Queue |
| 268 | Missing Number | Math, Bit Manipulation |
| 287 | Find the Duplicated Number | Brutal Force, Two Pointers, Divide and Conquer |
| 292 | Nim Game | Math |
| 371 | Sum of Two Integers | Bit Manipulation |
| 416 | Partition Equal Subset Sum | Dynamic Programming |
| 437 | Path Sum III | Backtracking (DFS) |
| 476 | Number Complement | Bit Manipulation |
| 507 | Perfect Number | Math |
| 516 | Longest Palindromic Subsequence | Dynamic Programming |
| 695 | Max Area of Island | Backtracking (DFS) |
| 725 | Split Linked List in Parts | Linked List |