Challenges
Test your skills
Solve coding challenges, earn points, and climb the leaderboard.
Easy
Two Sum
Given an array of integers, return indices of the two numbers that add up to a target.
Arrays 89 submissions
Medium
25 pts
Merge Intervals
Given an array of intervals, merge all overlapping intervals.
Arrays 52 submissions
Hard
50 pts
LRU Cache
Design a data structure that follows the constraints of a Least Recently Used cache.
Design 23 submissions
Easy
Valid Parentheses
Given a string containing just bracket characters, determine if the input string is valid.
Stack 95 submissions
Medium
25 pts
Binary Tree Level Order
Given a binary tree, return the level order traversal of its nodes' values.
Trees 41 submissions
Hard
50 pts
Word Search II
Given a 2D board and a list of words, find all words present in the board.
Trie 15 submissions