Top 50 Data Structures & Algorithms Questions Asked in Google Interviews

Learn Smarter with Real Mentors

As someone navigating the early stages of my career, I know how overwhelming it can feel. There are hundreds of questions, dozens of topics, and too little time. That’s why having a clear roadmap matters. And even better? Having mentors who’ve already walked the path.

This blog is my attempt to simplify your journey. Below, you’ll find 50 of the most frequently asked Data Structures & Algorithms (DSA) questions that appear in Google’s coding interviews. I’ve also included how to practice smart, not just hard.

Why Google Cares About DSA

You don’t just need the answer. You need to justify why it’s the best one. That’s why strong foundations in DSA matter so much. Let’s look at the questions.

The Top 50 DSA Questions (Grouped by Topic)

Arrays & Strings

  1. Longest Substring Without Repeating Characters
  2. Merge Intervals
  3. Trapping Rain Water
  4. Product of Array Except Self
  5. Container With Most Water
  6. Maximum Subarray (Kadane’s Algorithm)
  7. Longest Palindromic Substring
  8. Set Matrix Zeroes
  9. Rotate Image

Linked Lists

  1. Detect Cycle in Linked List
  2. Merge Two Sorted Lists
  3. Remove N-th Node From End
  4. Copy List with Random Pointer
  5. Intersection of Two Linked Lists
  6. Add Two Numbers

Trees & BSTs

  1. Validate Binary Search Tree
  2. Lowest Common Ancestor
  3. Level Order Traversal
  4. Serialize & Deserialize Binary Tree
  5. Maximum Path Sum
  6. Convert Sorted Array to BST

Recursion & Backtracking

  1. Permutations
  2. Combination Sum
  3. N-Queens Problem
  4. Sudoku Solver
  5. Word Search

Dynamic Programming

  1. House Robber
  2. Longest Increasing Subsequence
  3. 0/1 Knapsack
  4. Coin Change
  5. Palindromic Substrings
  6. Edit Distance
  7. Target Sum
  8. Best Time to Buy & Sell Stock (I, II, III)

Graphs & Greedy

  1. Clone Graph
  2. Course Schedule (Topological Sort)
  3. Dijkstra’s Algorithm
  4. Detect Cycle in Directed Graph
  5. Minimum Spanning Tree (Kruskal/Prim)
  6. Word Ladder

Heaps & Advanced Topics

  1. Find Median from Data Stream
  2. Top K Frequent Elements
  3. K Closest Points to Origin

How to Practice Effectively (From Someone Still Learning Too)

Here’s what works:

  • Brute-force first, then optimize step-by-step.
  • Use a timer. Practice solving under 30 minutes.
  • Speak aloud. Pretend you’re explaining to an interviewer.
  • Revisit problems after 1–2 weeks to retain logic.

And most importantly? Track what you’re weak at. For me, that was Graphs. For you, it might be DP or Backtracking. Identify it early.

Why I Recommend CodingWithIITians.com

  • Mentors from Amazon, Google, Uber (IIT alumni)
  • Live structured DSA classes with assignments
  • Mock interviews & resume reviews
  • 12-week roadmap built for FAANG-level prep

I wanted more than YouTube tutorials. I wanted real feedback, real deadlines, and mentors who’ve sat in Google interview rooms. That’s what this platform gives.

Final Thoughts: You Don’t Need to Be a Genius

You don’t need to be a genius. You just need:

  • Curiosity
  • Consistency
  • And the courage to keep going even when it’s tough

Solve a few problems every day. Be okay with failing. Keep learning. And trust that all the effort will add up.

Let’s crack it Together