Title Acceptance Level Single Number 65.5% Easy Convert Sorted Array to Binary Search Tree 57.9% Easy Contains Duplicate 56.0% Easy Verifying an Alien Dictionary 54.1% Easy Merge Two Sorted Lists 53.5% Easy Happy Number 50.4% Easy Add Strings 47.5% Easy Two Sum 45.6% Easy Bulls and Cows 42.4% Easy House Robber 42.0% Easy Intersection of Two Linked Lists 40.6% Easy Reverse Bits 39.8% Easy Valid Parentheses 39.0% Easy Contains Duplicate II 37.7% Easy Wiggle Sort 63.8% Medium IP to CIDR 61.7% Medium Convert to Base -2 59.0% Medium Smallest Common Region 58.8% Medium Design File System 56.8% Medium Combination Sum 56.1% Medium Kth Largest Element in an Array 55.4% Medium Pyramid Transition Matrix 54.6% Medium Flatten Nested List Iterator 52.9% Medium Koko Eating Bananas 52.1% Medium Robot Bounded In Circle 49.6% Medium Flatten 2D Vector 45.7% Medium Lowest Common Ancestor of a Binary Tree 45.7% Medium Design Circular Queue 43.7% Medium Pour Water 43.3% Medium Minimize Rounding Error to Meet Target 41.7% Medium Cheapest Flights Within K Stops 39.3% Medium Add and Search Word - Data structure design 38.1% Medium Maximal Square 37.7% Medium Basic Calculator II 36.9% Medium Find First and Last Position of Element in Sorted Array 36.2% Medium Coin Change 35.5% Medium Add Two Numbers 33.9% Medium Mini Parser 33.8% Medium Wiggle Sort II 29.9% Medium Longest Palindromic Substring 29.5% Medium Fraction to Recurring Decimal 21.6% Medium Contains Duplicate III 20.9% Medium Minimum Number of Flips to Convert Binary Matrix to Zero Matrix 69.5% Hard Employee Free Time 66.2% Hard Sliding Puzzle 59.3% Hard Maximum Candies You Can Get from Boxes 58.8% Hard Trapping Rain Water 48.9% Hard Guess the Word 46.1% Hard Design In-Memory File System 45.9% Hard Maximum Profit in Job Scheduling 44.0% Hard Merge k Sorted Lists 40.2% Hard Shortest Path to Get All Keys 40.1% Hard Word Search II 34.9% Hard Minimum Window Substring 34.6% Hard Palindrome Pairs 33.7% Hard Alien Dictionary 33.3% Hard Median of Two Sorted Arrays 29.6% Hard Text Justification 27.7% Hard Regular Expression Matching 26.8% Hard