Index of solved leetcode.com problems by category. Most links point to leetcode, unless there are two; in that case there is a wiki page with explanation. Mostly used for problems that are solved in multiple languages.

• 217. Contains Duplicate / Leetcode
• 268. Missing Number / Leetcode (Bit Manipulation, Sum first n integers)
• 448. Find All Numbers Disappeared in an Array / Leetcode
• 136. Single Number (Bit Manipulation, XOR)
• 1. Two Sum
• 977. Squares of a Sorted Array / Leetcode
• 88. Merge Sorted Array (Arrays, Two Pointers)
• 442. Find All Duplicates in an Array

• 121. Best Time to Buy and Sell Stock (Floyd's Algorithm)
• 876. Middle of the Linked List
• 287. Find the Duplicate Number (Floyd's Algorithm)
• 203. Remove Linked List Elements
• 83. Remove Duplicates from Sorted List
• 142. Linked List Cycle II
• 19. Remove Nth Node From End of List
• 234. Palindrome Linked List

• 21. Merge Two Sorted Lists
• 206. Reverse Linked List / Leetcode (In place reversal of linked list)
• 11. Container With Most Water / Leetcode

• 53. Maximum Subarray
• 70. Climbing Stairs / Leetcode
• 121. Best Time to Buy and Sell Stock
• 152. Maximum Product Subarray
• 322. Coin Change / Leetcode (Bottom Up, BFS)
• 494. Target Sum / Leetcode (DP, BU)

• 704. Binary Search
• 744. Find Smallest Letter Greater Than Target
• 852. Peak Index in a Mountain Array