Title Acceptance Level Height Checker 71.1% Easy Reverse Words in a String III 69.8% Easy Invert Binary Tree 65.0% Easy Fizz Buzz 62.3% Easy Design HashMap 61.3% Easy Check If a Number Is Majority Element in a Sorted Array 59.2% Easy Intersection of Two Arrays II 51.4% Easy Implement Queue using Stacks 49.6% Easy Symmetric Tree 46.8% Easy Maximum Subarray 46.5% Easy Two Sum 45.6% Easy Remove Duplicates from Sorted List 45.4% Easy Find Pivot Index 44.0% Easy Isomorphic Strings 39.8% Easy Valid Parentheses 39.0% Easy K-diff Pairs in an Array 31.6% Easy Permutations 63.5% Medium Generate Parentheses 62.7% Medium Product of Array Except Self 60.1% Medium Friend Circles 58.6% Medium Group Anagrams 56.9% Medium Rotate Image 56.7% Medium Find the Duplicate Number 55.5% Medium Kth Largest Element in an Array 55.4% Medium Integer to Roman 55.1% Medium Design Tic-Tac-Toe 54.3% Medium Shuffle an Array 52.8% Medium Top K Frequent Words 51.8% Medium Decode String 50.0% Medium Valid Sudoku 48.7% Medium Find the Smallest Divisor Given a Threshold 47.6% Medium Insert Delete GetRandom O(1) 47.5% Medium Number of Islands 46.8% Medium Letter Combinations of a Phone Number 46.8% Medium Lowest Common Ancestor of a Binary Tree 45.7% Medium Flatten 2D Vector 45.7% Medium Binary Tree Vertical Order Traversal 45.3% Medium Find Minimum in Rotated Sorted Array 45.1% Medium Search a 2D Matrix II 43.2% Medium Course Schedule 43.1% Medium Set Matrix Zeroes 43.1% Medium Longest Increasing Subsequence 42.6% Medium Word Break 40.1% Medium Merge Intervals 39.3% Medium Add and Search Word - Data structure design 38.1% Medium Remove Duplicates from Sorted List II 36.8% Medium Search in Rotated Sorted Array 34.5% Medium Design Snake Game 34.2% Medium Add Two Numbers 33.9% Medium LRU Cache 33.2% Medium Simplify Path 32.6% Medium Longest Substring Without Repeating Characters 30.4% Medium Word Ladder 29.6% Medium Largest Number 28.8% Medium Validate Binary Search Tree 27.8% Medium 3Sum 26.8% Medium Reverse Words in a String 21.9% Medium Maximum Frequency Stack 60.6% Hard Trapping Rain Water 48.9% Hard Serialize and Deserialize Binary Tree 47.5% Hard Design Search Autocomplete System 44.7% Hard Find Median from Data Stream 44.3% Hard Merge k Sorted Lists 40.2% Hard Word Search II 34.9% Hard The Skyline Problem 34.6% Hard Minimum Window Substring 34.6% Hard LFU Cache 34.2% Hard First Missing Positive 32.0% Hard Candy 31.6% Hard Reaching Points 29.4% Hard