Crack Coding Interviews with These 5 Free DSA Courses

I Tested 50+ Free DSA Courses in 6 Months Only These 5 Can Actually Get You Into FAANG!

Yes, you read that right! In the last 6 months, I literally tested 50+ free DSA (Data Structures & Algorithms) courses, and only 5 resources stood out the ones that actually help people crack FAANG interviews.

I also noticed a pattern:
95% of free resources only give basic, generic advice with copy-paste roadmaps. But these 5? They’re proven, recommended by top competitive programmers, and used by real candidates to get into companies like Google, Amazon, and Meta.

So in today’s guide, I’ll share exactly those free DSA resources and more importantly, how to use them the right way.

Because according to a report, even though millions of users are registered on LeetCode, less than 50% solve more than 100 problems. And around 80% of developers struggle with DSA-based interviews not because they lack resources, but because they don’t know how to use them strategically.

Glassdoor interview data also shows that every top tech company follows a specific pattern:

Google: 40% questions are graph-based
Amazon: 35% focus on trees and recursion
Microsoft: heavily leans on Dynamic Programming

So, random practice won’t help you need a targeted approach.

Here’s what we’ll cover today
1. Best Free Roadmap Resources
2. Topic-wise Best YouTube Channels + Practice Platforms (some hidden gems too!)
3. Company-specific preparation patterns
4. The right method to use these resources

All of this, in a structured and actionable way.

Step 1: Best Free DSA Roadmaps

Starting DSA without a roadmap is like shooting arrows in the dark.

The best free roadmap resource is Roadmap.sh. This site provides interactive structured roadmaps for almost everything from full-stack development to DSA. You can even track your progress and mark completed topics.

With over 2 million developers helped, this site will give you a clear learning path. Go there, open the DSA roadmap, and even print it out it’ll be your blueprint! Once your roadmap is clear, the next step is Practice Sheets.

There are tons of them online, but the best one in my experience is Striver’s A2Z DSA Sheet 450+ handpicked questions, all taken from real interviews. Each question comes with an article and video explanation. In fact, 78% of India’s top 500 competitive programmers recommend this sheet on LinkedIn.

Don’t make this mistake:
Don’t just open the sheet and start watching videos it’s not a Netflix series!
First, understand the roadmap → identify the topics → then start practicing systematically.

Step 2: Best Platforms to Practice DSA

Everyone knows about LeetCode, Codeforces, and HackerRank but there are some hidden gems too that most people ignore

CSES Problem Set: Created by Finland’s Olympiad team, includes 300 handpicked problems. The difficulty increases gradually, making it perfect for beginners to pros. Each problem also has community discussions below it.
Codeforces EDU: A structured course covering advanced topics like DP, segment trees, and graph theory. Designed at the standard of top coders.
Exercism.io: Lets you code and get real feedback from mentors for free! Every review feels like having a personal guide.

These three platforms are lesser-known but their quality is top-notch.

Step 3: Best YouTube Channels (Language-Wise)

Language matters! Here are the best YouTube channels for DSA in Hindi and English

Hindi Channels:

Aditya Verma: His videos are old but timeless. His pattern-based teaching makes complex topics like DP super simple.
Striver (Raj Vikramaditya): His A2Z DSA sheet + mentorship-style videos are a complete roadmap.
Code Help by Love Babbar: Great for CS fundamentals like DBMS, OS, and SQL explained with relatable examples.

English Channels:

NeetCode: Perfect for Python users. Clean code, optimized solutions, and strong pattern recognition focus.
Pepcoding: Excellent for Java learners. Builds rock-solid foundations from beginner to advanced.
Kunal Kushwaha: One-shot videos on OS, GitHub, and computer networks explained like an x-ray of the concept.
Hitesh Choudhary (Chai aur Code): Connects CS concepts with real-world use cases.

Step 4: The Right Way to Use These Resources

Just knowing resources isn’t enough how you use them makes all the difference.

Step 1 – Never start directly with videos

This isn’t a Netflix binge. First, list all algorithms for a topic. Google “ algorithms list” or use Striver’s sheet for guidance.

Step 2 – Read first, then watch

Always read an article before watching a video. Reading keeps you active in understanding videos can make you passive. Use sites like GeeksforGeeks, CP Algorithms, or Codeforces Blogs. If you still don’t get it, ask ChatGPT for help for example:

“Explain this line of code”
“Dry run this algorithm with an example”

Step 3 – The 30-Minute Rule

Whenever you solve a problem, give yourself at least 30 minutes to think before checking the solution. If it doesn’t work, dry run the code first, understand it step by step, and only then watch the video.

Step 4 – Take Notes (Mandatory!)

Always make notes while watching videos.
Write:

The core logic
Where you went wrong
How the video approached it differently
Edge cases you missed

Notes can be digital or physical but they must exist. They’re essential for revision.

Step 5 – The “10 Question Rule”

If you strictly follow this process for 10 problems, your brain will automatically start spotting patterns from the 11th one onwards. This is how top developers train their problem-solving mindset.

Step 5: Company-Specific Interview Patterns

Each company has its own interview focus. Based on Glassdoor + Blind data analysis, here’s what you need to know

Google

40% questions: Graphs (BFS, DFS, shortest path, connected components)
25%: Arrays & Strings (Two Pointers, Sliding Window)
20%: Trees
System Design for higher levels (L4+)
Focus more on graphs master Dijkstra, Floyd-Warshall, Tarjan’s algorithms.

Amazon

35%: Trees & Recursion
30%: Arrays & Strings
15%: Dynamic Programming
Also includes Leadership Principle-based behavioral rounds. Master Tree problems, then develop recursive thinking break problems into smaller versions until you reach the base case.

Meta (Facebook)

35%: Arrays & Hashing
25%: Graphs (Social Network-type problems)
20%: Strings
Also includes Product Sense rounds where business logic is tested. Build speed + accuracy on medium-level problems, and aim to solve at least 2 questions in 45 minutes.

Step 6: Hidden High-Quality Platforms for Serious Learners

Here are some lesser-known but world-class DSA resources

AlgoExpert: Paid, but even the free tier gives 30+ handpicked problems with detailed video explanations. Focuses more on patterns, not syntax.
Structy: A free course focused on Recursion and Trees amazing visual explanations make the code unfold before your eyes.
NeetCode.io: Official NeetCode website with 150 must-do problems explained via patterns (especially great for Python users).
CP Algorithms: Like an encyclopedia of advanced algorithms built by the Russian programming community.
USACO Guide: Offers a structured journey from Bronze to Platinum step-by-step growth, not just a roadmap.

Bonus for Absolute Beginners

If you’re a complete beginner and even basic programming feels confusing, start with Harvard’s CS50.

It’s one of the most powerful free CS courses ever made high production quality, legendary teaching by David Malan, and perfect for building a solid foundation. After CS50, your interest and clarity in computer science will skyrocket.

Final Advice

Start with Roadmap.sh, follow Striver’s A2Z Sheet, explore topic-wise YouTube channels, try out hidden practice platforms, and learn company patterns. But most importantly follow the right method and stay consistent.

Till then
Keep Learning, Keep Growing. ✨