LeetCode LeetCode Algorithm # Title Solution Difficulty 7 Reverse Integer C# Easy 8 String to Integer (atoi) C# Easy 9 Palindrome Number C# Easy 13 Roman to Integer C# Easy 21 Merge Two Sorted Lists C# Easy 24 Swap Nodes in Pairs C# Medium 26 Remove Duplicates from Sorted Array C# Easy 27 Remove Element Java Easy 36 Valid Sudoku Swift Easy 58 Length of Last Word C# Easy 66 Plus One C# Easy 70 Climbing Stairs C# Easy 83 Remove Duplicates from Sorted List C# Easy 100 Same Tree Java Easy 102 Binary Tree Level Order Traversal C# Easy 104 Maximum Depth of Binary Tree Java Easy 107 Binary Tree Level Order Traversal II C# Easy 110 Balanced Binary Tree C# Easy 111 Minimum Depth of Binary Tree Java Easy 112 Path Sum C# Easy 118 Pascal's Triangle C# Easy 119 Pascal's Triangle II C# Easy 141 Linked List Cycle C# Medium 155 Min Stack Java Easy 160 Intersection of Two Linked Lists C# Easy 169 Majority Element C# Easy 171 Excel Sheet Column Number C# Easy 172 Factorial Trailing Zeroes C# Easy 191 Number of 1 Bits C# Easy 198 House Robber C# Easy 202 Happy Number C# Easy 203 Remove Linked List Elements Java Easy 206 Reverse Linked List C# Easy 217 Contains Duplicate C# Easy 219 Contains Duplicate II C# Easy 223 Rectangle Area C# Easy 225 Implement Stack using Queues C# Medium 226 Invert Binary Tree C# Easy 231 Power of Two C# Easy 232 Implement Queue using Stacks C# Easy 237 Delete Node in a Linked List C# Easy 242 Valid Anagram C# Easy 257 Binary Tree Paths C# Easy 258 Add Digits Java Easy 283 Move Zeroes Java Easy 287 Find the Duplicate Number C# Hard 290 Word Pattern C# Easy 292 Nim Game Java Easy 299 Bulls and Cows C# Easy 303 Range Sum Query - Immutable Java Easy 326 Power of Three C# Easy 338 Counting Bits C# Medium 342 Power of Four C# Easy 344 Reverse String Java Easy 345 Reverse Vowels of a String C# Easy 349 Intersection of Two Arrays C# Easy 350 Intersection of Two Arrays II C# Easy 371 Sum of Two Integers C# Easy 374 Guess Number Higher or Lower C# Easy