leetcode_python status id Difficulty Title 1 Easy Two Sum 2 Medium Add Two Numbers 7 Medium Reverse Integer 9 Easy Palindrome Number 12 Medium Integer To Roman 13 Easy Roman to Integer 14 Easy Longest Common Prefix 16 Medium 3Sum Closest 17 Medium Letter Combination of a Phone Number 20 Easy Valid Parentheses 21 Easy Merge Two Sorted Lists 22 Medium Generate Parentheses 23 Hard Merge K Sorted Lists 24 Medium Swap Nodes in Pairs 27 Easy Remove Element 29 Medium Divide Two Integer 46 Medium Permutations 50 Medium Pow(x, n) 53 Medium Maximum Subarray 66 Easy Plus One 67 Easy Add Binary 69 Easy Sqrt(x) 70 Easy Climbing Stairs 72 Hard Edit Distance 100 Easy Same Tree 101 Easy Symmetric Tree 104 Easy Maximum Depth of Binary Tree 108 Easy Convert Sorted Array to Binary Search Tree 110 Easy Balanced Binary Tree 125 Easy Valid Palindrome 136 Easy Single Number 141 Easy Linked List Cycle 169 Easy Majority Element 190 Easy Reverse Bits 191 Easy Number of 1 Bits 198 Medium House Robber 206 Easy Reverse Linked List 217 Easy Contains Duplicate 225 Easy Implement Stack Using Queues 226 Easy Invert Binary Tree 232 Easy Implement Queue Using Stacks 234 Easy Palindrome Linked List 235 Medium Lowest Common Ancestor of a Binary Search Tree 242 Easy Valid Anagram 268 Easy Missing Number 278 Easy First Bad Version 283 Easy Move Zeroes 338 Easy Counting Bits 383 Easy Ransom Note 409 Easy Longest Palindrome 443 Medium String Compression 509 Easy Fibonacci Number 543 Easy Diameter of Binary Tree 564 Hard Find the Closest Palindrome 572 Easy Subtree of Another Tree 704 Easy Binary Search 733 Easy Flood Fill 746 Easy Min Cost Climbing Stairs 844 Easy Backspace String Compare 876 Easy Middle of the Linked List 977 Easy Squares of a Sorted Array 1137 Easy N-th Tribonacci Number 1491 Easy Average Salary Excluding the Minimum and Maximum Salary 1721 Medium Swapping Nodes in a Linked List 1822 Easy Sign of the Product of an Array 2140 Medium Solving Questions With Brainpower 2215 Easy Find the Difference of Two Arrays