Leetcode Problem Solved: 88 (Easy: 38, Medium: 49, Hard: 1) # Title Solutions Difficulty 00001 Two Sum Easy 00003 Longest Substring Without Repeating Characters Medium 00005 Longest Palindromic Substring Medium 00011 Container With Most Water Medium 00015 3Sum Medium 00019 Remove Nth Node From End of List Medium 00020 Valid Parentheses Easy 00021 Merge Two Sorted Lists Easy 00024 Swap Nodes in Pairs Medium 00025 Reverse Nodes in k-Group Hard 00033 Search in Rotated Sorted Array Medium 00038 Count and Say Medium 00048 Rotate Image Medium 00050 Pow(x, n) Medium 00053 Maximum Subarray Medium 00067 Add Binary Easy 00070 Climbing Stairs Easy 00071 Simplify Path Medium 00075 Sort Colors Medium 00094 Binary Tree Inorder Traversal Easy 00095 Unique Binary Search Trees II Medium 00098 Validate Binary Search Tree Medium 00100 Same Tree Easy 00101 Symmetric Tree Easy 00102 Binary Tree Level Order Traversal Medium 00104 Maximum Depth of Binary Tree Easy 00105 Construct Binary Tree from Preorder and Inorder Traversal Medium 00106 Construct Binary Tree from Inorder and Postorder Traversal Medium 00108 Convert Sorted Array to Binary Search Tree Easy 00111 Minimum Depth of Binary Tree Easy 00116 Populating Next Right Pointers in Each Node Medium 00118 Pascal's Triangle Easy 00119 Pascal's Triangle II Easy 00128 Longest Consecutive Sequence Medium 00133 Clone Graph Medium 00134 Gas Station Medium 00144 Binary Tree Preorder Traversal Easy 00145 Binary Tree Postorder Traversal Easy 00146 LRU Cache Medium 00150 Evaluate Reverse Polish Notation Medium 00155 Min Stack Easy 00200 Number of Islands Medium 00203 Remove Linked List Elements Easy 00206 Reverse Linked List Easy 00215 Kth Largest Element in an Array Medium 00217 Contains Duplicate Easy 00225 Implement Stack using Queues Easy 00230 Kth Smallest Element in a BST Medium 00232 Implement Queue using Stacks Easy 00235 Lowest Common Ancestor of a Binary Search Tree Easy 00236 Lowest Common Ancestor of a Binary Tree Medium 00240 Search a 2D Matrix II Medium 00257 Binary Tree Paths Easy 00279 Perfect Squares Medium 00283 Move Zeroes Easy 00344 Reverse String Easy 00347 Top K Frequent Elements Medium 00350 Intersection of Two Arrays II Easy 00371 Sum of Two Integers Medium 00387 First Unique Character in a String Easy 00389 Find the Difference Easy 00394 Decode String Medium 00429 N-ary Tree Level Order Traversal Medium 00450 Delete Node in a BST Medium 00494 Target Sum Medium 00509 Fibonacci Number Easy 00542 01 Matrix Medium 00572 Subtree of Another Tree Easy 00575 Distribute Candies Easy 00606 Construct String from Binary Tree Easy 00617 Merge Two Binary Trees Easy 00622 Design Circular Queue Medium 00637 Average of Levels in Binary Tree Easy 00692 Top K Frequent Words Medium 00700 Search in a Binary Search Tree Easy 00721 Accounts Merge Medium 00733 Flood Fill Easy 00739 Daily Temperatures Medium 00752 Open the Lock Medium 00783 Minimum Distance Between BST Nodes Easy 00797 All Paths From Source to Target Medium 00814 Binary Tree Pruning Medium 00841 Keys and Rooms Medium 00863 All Nodes Distance K in Binary Tree Medium 00912 Sort an Array Medium 00994 Rotting Oranges Medium 01091 Shortest Path in Binary Matrix Medium 01971 Find if Path Exists in Graph Easy