Namaste DSA Sheet: Data Structures & Algorithms

The Namaste DSA Sheet organizes coding interview questions by topic, with practice links, video explanations and reading resources where available. Filter questions by difficulty or company, and sign in to bookmark questions and track your progress.

New to data structures and algorithms? Follow the DSA learning roadmap or explore the Namaste DSA course for lessons alongside your practice.

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Question	Companies	Practice	Video	Editorial	Difficulty
Sum	Companies	Practice	Video	Editorial	Easy
Second Largest	Companies	Practice	Video	Editorial	Easy
Palindrome Number	Companies	Practice	Video	Editorial	Easy
Reverse Integer	Companies	Practice	Video	Editorial	Medium
Count Negative Numbers in an Array	Companies	Practice	Video	Editorial	Easy
Find Smallest Number in an Array	Companies	Practice	Video	Editorial	Easy
Find Largest Number in an Array	Companies	Practice	Video	Editorial	Medium
Binary Search	Companies	Practice	Video	Editorial	Easy
Merge Sort	Companies	Practice	Video	Editorial	Medium
Power of Two	Companies	Practice	Video	Editorial	Easy

Question	Companies	Practice	Video	Editorial	Difficulty
Remove Duplicates	Companies	Practice	Video	Editorial	Easy
Remove Element	Companies	Practice	Video	Editorial	Easy
Reverse String	Companies	Practice	Video	Editorial	Easy
Best Time to Buy and Sell Stocks	Companies	Practice	Video	Editorial	Easy
Merge Sorted Arrays	Companies	Practice	Video	Editorial	Easy
Move Zeros	Companies	Practice	Video	Editorial	Easy
Max Consecutive Ones	Companies	Practice	Video	Editorial	Easy
Missing Number	Companies	Practice	Video	Editorial	Easy
Single Number	Companies	Practice	Video	Editorial	Easy

Question	Companies	Practice	Video	Editorial	Difficulty
Design Linked List	Companies	Practice	Video	Editorial	Medium
Middle of Linked List	Companies	Practice	Video	Editorial	Easy
Reverse Linked List	Companies	Practice	Video	Editorial	Easy
Linked List Cycle	Companies	Practice	Video	Editorial	Easy
Palindrome Linked List	Companies	Practice	Video	Editorial	Easy
Intersection of two Linked Lists	Companies	Practice	Video	Editorial	Easy
Remove Linked List Elements	Companies	Practice	Video	Editorial	Easy
Remove nth node from end of List	Companies	Practice	Video	Editorial	Medium
Remove Duplicates from Sorted List	Companies	Practice	Video	Editorial	Easy
Odd Even Linked List	Companies	Practice	Video	Editorial	Medium
Add Two Numbers	Companies	Practice	Video	Editorial	Medium
Merge Two Sorted Lists	Companies	Practice	Video	Editorial	Easy
Rotate List	Companies	Practice	Video	Editorial	Medium
Swap Nodes in Pairs	Companies	Practice	Video	Editorial	Medium

Question	Companies	Practice	Video	Editorial	Difficulty
Length of Last Word	Companies	Practice	Video	Editorial	Easy
Find Words Containing Character	Companies	Practice	Video	Editorial	Easy
Jewels and Stones	Companies	Practice	Video	Editorial	Easy
Find Most Frequent Vowel and Consonant	Companies	Practice	Video	Editorial	Easy
Split a String in Balanced Strings	Companies	Practice	Video	Editorial	Easy
Reverse String II	Companies	Practice	Video	Editorial	Easy
Valid Palindrome	Companies	Practice	Video	Editorial	Easy
Largest Odd Number in a String	Companies	Practice	Video	Editorial	Easy
Longest Common Prefix	Companies	Practice	Video	Editorial	Easy
Valid Anagram	Companies	Practice	Video	Editorial	Easy
Isomorphic Strings	Companies	Practice	Video	Editorial	Easy
Group Anagrams	Companies	Practice	Video	Editorial	Medium
Minimum Add to Make Parentheses Valid	Companies	Practice	Video	Editorial	Medium
Reverse Words in a String	Companies	Practice	Video	Editorial	Medium
Sum of Beauty of All Substrings	Companies	Practice	Video	Editorial	Medium
Decode String	Companies	Practice	Video	Editorial	Medium
Count and Say	Companies	Practice	Video	Editorial	Medium
Reorganize String	Companies	Practice	Video	Editorial	Medium
Repeated String Match	Companies	Practice	Video	Editorial	Medium

Question	Companies	Practice	Video	Editorial	Difficulty
Implement Stack	Companies	Practice	Video	Editorial	Easy
Implement Queue using Stacks	Companies	Practice	Video	Editorial	Easy
Valid Parentheses	Companies	Practice	Video	Editorial	Easy
Min Stack	Companies	Practice	Video	Editorial	Easy
Remove Outermost Parentheses	Companies	Practice	Video	Editorial	Easy
Evaluate Reverse Polish Notation	Companies	Practice	Video	Editorial	Medium
Next Greater Element	Companies	Practice	Video	Editorial	Easy
Daily Temperatures	Companies	Practice	Video	Editorial	Medium
Next Greater Element - II	Companies	Practice	Video	Editorial	Medium
Rotting Oranges	Companies	Practice	Video	Editorial	Medium

Question	Companies	Practice	Video	Editorial	Difficulty
Square Root of X	Companies	Practice	Video	Editorial	Easy
Guess Higher or Lower	Companies	Practice	Video	Editorial	Easy
Search in Rotated Sorted Array	Companies	Practice	Video	Editorial	Medium
First Bad Version	Companies	Practice	Video	Editorial	Easy
Find Peak Element	Companies	Practice	Video	Editorial	Medium
Find Minimum in Rotated Sorted Array	Companies	Practice	Video	Editorial	Medium
Find First & Last Position in Sorted Array	Companies	Practice	Video	Editorial	Medium
Find Peak in a Mountain Array	Companies	Practice	Video	Editorial	Easy
Single Element in a Sorted Array	Companies	Practice	Video	Editorial	Medium
Find k Closest Elements	Companies	Practice	Video	Editorial	Medium

Question	Companies	Practice	Video	Editorial	Difficulty
Two Sum	Companies	Practice	Video	Editorial	Easy
Two Sum II	Companies	Practice	Video	Editorial	Easy
Is Subsequence	Companies	Practice	Video	Editorial	Easy
Find Index of First Occurrence in String	Companies	Practice	Video	Editorial	Easy
Intersection of Two Linked Lists	Companies	Practice	Video	Editorial	Easy
Container with Most Water	Companies	Practice	Video	Editorial	Medium
Three Sum	Companies	Practice	Video	Editorial	Medium
Trapping Rain Water	Companies	Practice	Video	Editorial	Hard
Longest Substring Without Repeating Characters	Companies	Practice	Video	Editorial	Medium
Longest Repeating Character Replacement	Companies	Practice	Video	Editorial	Medium
Permutation in String	Companies	Practice	Video	Editorial	Medium
Sliding Window Maximum	Companies	Practice	Video	Editorial	Hard

Question	Companies	Practice	Video	Editorial	Difficulty
Preorder Traversal	Companies	Practice	Video	Editorial	Easy
Inorder Traversal	Companies	Practice	Video	Editorial	Easy
Postorder Traversal	Companies	Practice	Video	Editorial	Easy
Level Order Traversal	Companies	Practice	Video	Editorial	Medium
Maximum Depth of Binary Tree	Companies	Practice	Video	Editorial	Easy
Path Sum	Companies	Practice	Video	Editorial	Easy
Symmetric Tree	Companies	Practice	Video	Editorial	Easy
Invert a Binary Tree	Companies	Practice	Video	Editorial	Easy
Same Tree	Companies	Practice	Video	Editorial	Easy
Balanced Binary Tree	Companies	Practice	Video	Editorial	Easy
Diameter of a Binary Tree	Companies	Practice	Video	Editorial	Easy
Zigzag Level Order Traversal	Companies	Practice	Video	Editorial	Medium
Subtree of another Tree	Companies	Practice	Video	Editorial	Easy
Lowest Common Ancestor	Companies	Practice	Video	Editorial	Medium
Binary Tree Right Side View	Companies	Practice	Video	Editorial	Medium
Count Good Nodes in Binary Tree	Companies	Practice	Video	Editorial	Medium
Populating Next Right Pointers in Each Node	Companies	Practice	Video	Editorial	Medium
Binary Tree Maximum Path Sum	Companies	Practice	Video	Editorial	Hard

Question	Companies	Practice	Video	Editorial	Difficulty
Valid Binary Search Tree	Companies	Practice	Video	Editorial	Medium
Search in a BST	Companies	Practice	Video	Editorial	Easy
Insert into a BST	Companies	Practice	Video	Editorial	Medium
Kth Smallest Element	Companies	Practice	Video	Editorial	Medium
Lowest Common Ancestor of a BST	Companies	Practice	Video	Editorial	Medium

Question	Companies	Practice	Video	Editorial	Difficulty
Kth Largest Element in an Array	Companies	Practice	Video	Editorial	Medium
Kth Largest Element in a Stream	Companies	Practice	Video	Editorial	Medium
Last Stone Weight	Companies	Practice	Video	Editorial	Easy
Top K Frequent Elements	Companies	Practice	Video	Editorial	Medium
Kth Smallest Element in a Sorted Matrix	Companies	Practice	Video	Editorial	Medium

Question	Companies	Practice	Video	Editorial	Difficulty
Subsets - The Power Set	Companies	Practice	Video	Editorial	Medium
Combinations	Companies	Practice	Video	Editorial	Medium
Permutations	Companies	Practice	Video	Editorial	Medium
Subset - II	Companies	Practice	Video	Editorial	Medium
Combination Sum	Companies	Practice	Video	Editorial	Medium
Combination Sum - II	Companies	Practice	Video	Editorial	Medium
Combination Sum - III	Companies	Practice	Video	Editorial	Medium
Letter Combinations of a Phone Number	Companies	Practice	Video	Editorial	Medium
Permutations - II	Companies	Practice	Video	Editorial	Medium
Palindrome Partitioning	Companies	Practice	Video	Editorial	Medium
Word Search	Companies	Practice	Video	Editorial	Medium
N Queens	Companies	Practice	Video	Editorial	Hard

Question	Companies	Practice	Video	Editorial	Difficulty
Two City Scheduling	Companies	Practice	Video	Editorial	Medium
Assign Cookies	Companies	Practice	Video	Editorial	Easy
Lemonade Change	Companies	Practice	Video	Editorial	Easy
Best Time to Buy and Sell Stock - II	Companies	Practice	Video	Editorial	Medium
Insert Interval	Companies	Practice	Video	Editorial	Medium
Merge Intervals	Companies	Practice	Video	Editorial	Medium
Partition Labels	Companies	Practice	Video	Editorial	Medium
Non Overlapping Intervals	Companies	Practice	Video	Editorial	Medium
Task Scheduler	Companies	Practice	Video	Editorial	Medium
Gas Station	Companies	Practice	Video	Editorial	Medium
Car Pooling	Companies	Practice	Video	Editorial	Medium
Candy	Companies	Practice	Video	Editorial	Hard

Question	Companies	Practice	Video	Editorial	Difficulty
Climbing Stairs	Companies	Practice	Video	Editorial	Easy
Minimum Cost Climbing Stairs	Companies	Practice	Video	Editorial	Easy
House Robber	Companies	Practice	Video	Editorial	Medium
House Robber II	Companies	Practice	Video	Editorial	Medium
Coin Change	Companies	Practice	Video	Editorial	Medium
Palindromic Substrings	Companies	Practice	Video	Editorial	Medium
Longest Palindromic Substring	Companies	Practice	Video	Editorial	Medium
Decode Ways	Companies	Practice	Video	Editorial	Medium
Maximum Subarray	Companies	Practice	Video	Editorial	Easy
Maximum Product Subarray	Companies	Practice	Video	Editorial	Medium
Word Break	Companies	Practice	Video	Editorial	Medium
Longest Increasing Subsequence	Companies	Practice	Video	Editorial	Medium
Partition Equal Subset Sum	Companies	Practice	Video	Editorial	Medium
Coin Change II	Companies	Practice	Video	Editorial	Medium
Unique Paths	Companies	Practice	Video	Editorial	Medium
Jump Game	Companies	Practice	Video	Editorial	Medium
Jump Game II	Companies	Practice	Video	Editorial	Medium
Minimum Cost to Cut a Stick	Companies	Practice	Video	Editorial	Hard
Super Egg Drop	Companies	Practice	Video	Editorial	Hard

Question	Companies	Practice	Video	Editorial	Difficulty
Clone Graph	Companies	Practice	Video	Editorial	Medium
Find if Path Exists in Graph	Companies	Practice	Video	Editorial	Medium
All Paths From Source to Target	Companies	Practice	Video	Editorial	Medium
Reconstruct Itinerary	Companies	Practice	Video	Editorial	Medium
Detect Cycle in Undirected Connected Graph	Companies	Practice	Video	Editorial	Medium
Topological Sort (DFS)	Companies	Practice	Video	Editorial	Medium
Number of Operations to Make Network Connected	Companies	Practice	Video	Editorial	Medium
Cheapest Flights Within K Stops	Companies	Practice	Video	Editorial	Medium
Number of Ways to Arrive at Destination	Companies	Practice	Video	Editorial	Medium
Min Cost to Connect All Points	Companies	Practice	Video	Editorial	Medium

More Resources & Guides

Namaste DSA Sheet: Data Structures & Algorithms

Overall Progress

Foundation

Arrays

Linked List

Strings

Stack and Queues

Binary Search Algorithm

Two Pointers & Sliding Window

Binary Tree

Binary Search Tree

Heap

Backtracking

Greedy Algorithm

Dynamic Programming

Graphs

More Resources & Guides