Data Structure I Title Solution 217. Contains Duplicate C++ 53. Maximum Subarray C++ 1. Two Sum C++ 88. Merge Sorted Array C++ 350. Intersection of Two Arrays II C++ 121. Best Time to Buy and Sell Stock C++ 566. Reshape the Matrix C++ 118. Pascal's Triangle C++ 36. Valid Sudoku C++ 74. Search a 2D Matrix C++ 387. First Unique Character in a String C++ 383. Ransom Note C++ 242. Valid Anagram C++ 141. Linked List Cycle C++ 21. Merge Two Sorted Lists C++ 206. Reverse Linked List C++ 83. Remove Duplicates from Sorted List C++ 20. Valid Parentheses C++ 232. Implement Queue using Stacks C++ 144. Binary Tree Preorder Traversal C++ 94. Binary Tree Inorder Traversal C++ 145. Binary Tree Postorder Traversal C++ 102. Binary Tree Level Order Traversal C++ 104. Maximum Depth of Binary Tree C++ 101. Symmetric Tree C++ 226. Invert Binary Tree C++ 112. Path Sum C++ 700. Search in a Binary Search Tree C++ 701. Insert into a Binary Search Tree C++ 98. Validate Binary Search Tree C++ 653. Two Sum IV - Input is a BST C++ 235. Lowest Common Ancestor of a Binary Search Tree C++ Data Structure II Title Solution 136. Single Number C++ 169. Majority Element C++ 15. 3Sum C++ 75. Sort Colors C++ 56. Merge Intervals C++ 706. Design HashMap C++ 119. Pascal's Triangle II C++ 48. Rotate Image C++ 59. Spiral Matrix II C++ 240. Search a 2D Matrix II C++ 435. Non-overlapping Intervals C++ 334. Increasing Triplet Subsequence C++ 238. Product of Array Except Self C++ 560. Subarray Sum Equals K C++ 415. Add Strings C++ 409. Longest Palindrome C++ 290. Word Pattern C++ 763. Partition Labels C++ 49. Group Anagrams C++ 43. Multiply Strings C++ 187. Repeated DNA Sequences C++ 5. Longest Palindromic Substring C++ 2. Add Two Numbers C++ 142. Linked List Cycle II C++ Algorithm I Title Solution 704. Binary Search C++ 278. First Bad Version C++ 35. Search Insert Position C++ 977. Squares of a Sorted Array C++ 189. Rotate Array C++ 283. Move Zeroes C++ 167. Two Sum II - Input Array Is Sorted C++ 344. Reverse String C++ 557. Reverse Words in a String III C++ 876. Middle of the Linked List C++ 19. Remove Nth Node From End of List C++ 3. Longest Substring Without Repeating Characters C++ 567. Permutation in String C++ 733. Flood Fill C++ 695. Max Area of Island C++ 617. Merge Two Binary Trees C++ 116. Populating Next Right Pointers in Each Node C++ 542. 01 Matrix C++ 994. Rotting Oranges C++ 21. Merge Two Sorted Lists C++ 206. Reverse Linked List C++ 77. Combinations C++ 46. Permutations C++ 784. Letter Case Permutation C++ 70. Climbing Stairs C++ 198. House Robber C++ 120. Triangle C++ 231. Power of Two C++ 191. Number of 1 Bits C++ 190. Reverse Bits C++ 136. Single Number C++