DSA Concepts & Practice Problems

Structured Data Structures & Algorithms learning paths and free practice problems, each with an in-browser editor, auto-judging, and step-wise AI hints.

Learning paths

• Array Basics: DSA Learning Path
• Hashing Pattern: DSA Learning Path
• Two Pointers: DSA Learning Path
• Sliding Window: DSA Learning Path
• Stacks & Queues: DSA Learning Path
• Linked Lists: DSA Learning Path
• Trees: DSA Learning Path
• Searching & Sorting: DSA Learning Path

Foundations: interactive visual guides

• Tree Foundations: Interactive Visual Guide
• Graph Foundations: Interactive Visual Guide
• Dynamic Programming Foundations: Interactive Visual Guide
• Tree Coding Basics: Interactive Visual Guide
• Sorting Foundations: Interactive Visual Guide
• Linked List Foundations: Interactive Visual Guide
• Recursion Foundations: Interactive Visual Guide
• Binary Search Foundations: Interactive Visual Guide

Practice problems

• Add Two Numbers: Medium DSA Practice with AI Hints
• Basic Calculator: Medium DSA Practice with AI Hints
• Best Time to Buy and Sell Stock: Easy DSA Practice with AI Hints
• Binary Search Foundations: Beginner DSA Practice with AI Hints
• Binary Search: Easy DSA Practice with AI Hints
• Binary Tree Inorder Traversal: Easy DSA Practice with AI Hints
• Binary Tree Maximum Path Sum: Hard DSA Practice with AI Hints
• Binary Tree Postorder Traversal: Easy DSA Practice with AI Hints
• Binary Tree Preorder Traversal: Easy DSA Practice with AI Hints
• Climbing Stairs: Easy DSA Practice with AI Hints
• Clone Graph: Medium DSA Practice with AI Hints
• Coin Change: Medium DSA Practice with AI Hints
• Construct Binary Tree from Preorder & Inorder: Hard DSA Practice with AI Hints
• Container With Most Water: Medium DSA Practice with AI Hints
• Contains Duplicate: Easy DSA Practice with AI Hints
• Course Schedule II: Medium DSA Practice with AI Hints
• Course Schedule: Medium DSA Practice with AI Hints
• Daily Temperatures: Medium DSA Practice with AI Hints
• Decode Ways: Medium DSA Practice with AI Hints
• Diameter of Binary Tree: Medium DSA Practice with AI Hints
• Dynamic Programming Concepts: Foundation DSA Practice with AI Hints
• Evaluate Reverse Polish Notation: Medium DSA Practice with AI Hints
• Fibonacci Number: Easy DSA Practice with AI Hints
• Find All Duplicates in an Array: Medium DSA Practice with AI Hints
• Find First and Last Position: Medium DSA Practice with AI Hints
• Find Minimum in Rotated Sorted Array: Medium DSA Practice with AI Hints
• First Missing Positive: Hard DSA Practice with AI Hints
• Flood Fill: Easy DSA Practice with AI Hints
• Greatest Common Divisor of Strings: Easy DSA Practice with AI Hints
• Generate Parentheses: Medium DSA Practice with AI Hints
• Graph Valid Tree: Medium DSA Practice with AI Hints
• Graphs Concepts: Foundation DSA Practice with AI Hints
• Group Anagrams: Medium DSA Practice with AI Hints
• House Robber II: Medium DSA Practice with AI Hints
• House Robber: Medium DSA Practice with AI Hints
• Invert Binary Tree: Easy DSA Practice with AI Hints
• Kth Largest Element in an Array: Medium DSA Practice with AI Hints
• Largest Rectangle in Histogram: Hard DSA Practice with AI Hints
• Binary Tree Level Order Traversal: Medium DSA Practice with AI Hints
• Linked List Foundations: Foundation DSA Practice with AI Hints
• Linked List Cycle: Easy DSA Practice with AI Hints
• Longest Common Subsequence: Hard DSA Practice with AI Hints
• Longest Consecutive Sequence: Medium DSA Practice with AI Hints
• Longest Increasing Subsequence: Hard DSA Practice with AI Hints
• Longest Repeating Character Replacement: Medium DSA Practice with AI Hints
• Longest Substring Without Repeating: Medium DSA Practice with AI Hints
• Lowest Common Ancestor of a Binary Tree: Medium DSA Practice with AI Hints
• Majority Element: easy DSA Practice with AI Hints
• Max Area of Island: Medium DSA Practice with AI Hints
• Maximum Depth of Binary Tree: Easy DSA Practice with AI Hints
• Maximum Subarray Sum of Size K: Easy DSA Practice with AI Hints
• Maximum Subarray: Medium DSA Practice with AI Hints
• Maximum Product Subarray: medium DSA Practice with AI Hints
• Median of Two Sorted Arrays: Hard DSA Practice with AI Hints
• Merge K Sorted Lists: Hard DSA Practice with AI Hints
• Merge Sorted Array: Easy DSA Practice with AI Hints
• Merge Strings Alternately: Easy DSA Practice with AI Hints
• Merge Two Sorted Lists: Easy DSA Practice with AI Hints
• Min Cost Climbing Stairs: Easy DSA Practice with AI Hints
• Min Stack: Medium DSA Practice with AI Hints
• Minimum Window Substring: Hard DSA Practice with AI Hints
• Missing Number in Array: Easy DSA Practice with AI Hints
• Move All Zeros to End: Easy DSA Practice with AI Hints
• Next Greater Element: Easy DSA Practice with AI Hints
• Number of Connected Components: Medium DSA Practice with AI Hints
• Number of Islands: Medium DSA Practice with AI Hints
• Pacific Atlantic Water Flow: Hard DSA Practice with AI Hints
• Partition Equal Subset Sum: Hard DSA Practice with AI Hints
• Partition Labels: Medium DSA Practice with AI Hints
• Path Sum: Easy DSA Practice with AI Hints
• Permutation in String: Medium DSA Practice with AI Hints
• Power of X (Pow(x, n)): Medium DSA Practice with AI Hints
• Product of Array Except Self: Medium DSA Practice with AI Hints
• Recursion Foundations: Foundation DSA Practice with AI Hints
• Remove Duplicates from Sorted Array: Easy DSA Practice with AI Hints
• Remove Nth Node From End of List: Medium DSA Practice with AI Hints
• Reorder List: Medium DSA Practice with AI Hints
• Reverse Linked List: Easy DSA Practice with AI Hints
• Reverse String: Easy DSA Practice with AI Hints
• Reverse Vowels of a String: Easy DSA Practice with AI Hints
• Reverse Words in a String: Medium DSA Practice with AI Hints
• Rotting Oranges: Medium DSA Practice with AI Hints
• Same Tree: Easy DSA Practice with AI Hints
• Search in Rotated Sorted Array: Medium DSA Practice with AI Hints
• Search Insert Position: Easy DSA Practice with AI Hints
• Sliding Window Maximum: Hard DSA Practice with AI Hints
• Sort an Array: Medium DSA Practice with AI Hints
• Sort Colors: Medium DSA Practice with AI Hints
• Sorting Algorithm Foundations: Foundation DSA Practice with AI Hints
• Squares of a Sorted Array: Easy DSA Practice with AI Hints
• String Compression: Medium DSA Practice with AI Hints
• Subarray Sum Equals K: Medium DSA Practice with AI Hints
• Symmetric Tree: Easy DSA Practice with AI Hints
• 3Sum: Medium DSA Practice with AI Hints
• Top K Frequent Elements: Medium DSA Practice with AI Hints
• Trapping Rain Water: Hard DSA Practice with AI Hints
• Trees Concepts: Foundation DSA Practice with AI Hints
• Two Sum II: Easy DSA Practice with AI Hints
• Two Sum: Easy DSA Practice with AI Hints
• Unique Paths: Medium DSA Practice with AI Hints
• Valid Anagram: Easy DSA Practice with AI Hints
• Valid Palindrome: Easy DSA Practice with AI Hints
• Valid Parentheses: Easy DSA Practice with AI Hints
• Validate Binary Search Tree: Medium DSA Practice with AI Hints
• Word Break: Medium DSA Practice with AI Hints
• Word Ladder: Hard DSA Practice with AI Hints