System Design Interview Prep:
A Beginner's Roadmap

Master core concepts, components, and strategies to crack your next interview with confidence.

Introduction

👋 Hey, Future Techies!

Have you ever scrolled through LinkedIn and seen “Got into Microsoft 🎉” from someone your age — and thought, “How??” Well, let’s decode exactly how Ankit, an IITian from a tier-2 branch, cracked Microsoft in just 3 months. No fluff, just real strategies, mistakes, and breakthroughs.

🛣️ The Starting Point: Not a Genius, Just Hungry

Contrary to what most people believe, Ankit wasn’t solving 5 LeetCode hards a day. In fact, until his second year, he didn’t even know what DSA was.

But once he decided Microsoft was the dream, he made a 3-month game plan, with no Plan B.

Month-wise Strategy

📅 Month 1: Mastering DSA (Data Structures & Algorithms)

📘 Resources Used:

GeeksforGeeks
LeetCode
Coding with IITians

🔄 Daily Routine:

6 hours/day of coding 🧑‍💻
2 hours of theory (DSA roadmap)
4 hours of problem-solving (starting with easy → medium)

“I didn’t jump to hards. I mastered the basics. Even sorting made me cry at first.” — Ankit

✨ Focus Topics:

Arrays & Strings
HashMaps & Sets
Recursion & Backtracking
Linked Lists (yeah, every damn type)

✅ He did 75 DSA problems in the first month. Nothing crazy, but consistent.

📅 Month 2: Applied DSA + Mock Interviews

📚 What Changed:

Switched to time-bound problems (30 min per problem)
Started participating in mock interviews on InterviewBit

💡 Tip:

Don’t just solve a problem. Revisit why a brute force fails. That’s what interviewers grill on.

📅 Month 3: Microsoft-Specific Prep 🔍

This is where things got real.
Ankit started studying Microsoft’s interview pattern.

🏢 Microsoft’s Common Rounds:

Online Assessment (OA)
DSA Round
System Design (basic for freshers)
Behavioral + Hiring Manager

🎯 Focus Areas:

Binary Search, Sliding Window, DP
Puzzle-style problems
Low-level design basics (just interfaces, API thinking)

He also used Glassdoor and Reddit for interview experiences.
E.g., r/cscareerquestionsIN

✍️ HR Round Prep:

He used the STAR method to frame answers:
Situation — Task — Action — Result

Example:

“Tell me a time you failed.”
Ankit talked about a failed college hackathon and how it taught him real-time debugging under pressure.

💬 Interview Day

📅 1st Round: DSA

2 questions, 1 easy (Matrix traversal), 1 medium (Binary Tree Path Sum)
Completed both in time. Clean code. Edge cases discussed.

📅 2nd Round: System Design

Asked to design a URL shortener
He focused on:
API design
Database schema
Scalability
Load balancing (just mentioned, didn’t dive too deep)

📅 3rd Round: Hiring Manager

Why Microsoft?
What if you get stuck in a team you hate?
How do you learn things fast?

He was honest. Not over-rehearsed. Showed curiosity.

📬 The Offer Letter

10 days later, the subject line read:

“Welcome to Microsoft!” 🎉

He cried. Called his parents. Updated his resume and LinkedIn.

🚀 What YOU Can Learn from This

✅ What Worked:

Consistency > Intensity
6 hours daily was realistic, not toxic.
Smart resource use
No 10+ courses. Just 2–3 that he stuck with till the end.
Mock interviews
Practicing real scenarios beat passive watching.
Understanding the company
He wasn’t just coding; he was preparing for Microsoft.

🚫 What Didn’t Work:

He tried balancing college fests + prep in Month 1 — didn’t work.
Tried doing System Design too early — waste of time.

❤️ Final Words

Ankit isn’t just an IITian. He’s someone who wanted it bad enough to fight through imposter syndrome, burnouts, and late nights. Whether you’re from an IIT or a tier-3 college, if you treat 3 months like it’s all you’ve got — results will show.

✨ So if you’re reading this on your 4th cup of coffee, wondering if you’re cut out for this — you are. Just start. One day, one problem, one resume line at a time.

FAQs

Q1. How did the IITian prepare for the Microsoft interview?
Most focused on data structures, algorithms, and problem-solving using platforms like LeetCode, GeeksforGeeks, and InterviewBit. Consistency mattered more than cramming right before the interview.

Q2. What kind of questions did Microsoft ask?
Microsoft typically asks coding questions, system design problems, and behavioral questions. The coding round included DSA problems (arrays, graphs, DP, trees), while the interviews tested problem-solving approach, optimization, and clarity of thought.

Q3. Did the IITian only rely on academics?
No. While a strong CS foundation from IIT helped, interview success came from extra practice on real interview questions, mock interviews, and internships/projects that showcased problem-solving skills.

Q4. How important were projects and internships?
Very important. Real-world projects demonstrated practical application of concepts, while internships gave exposure to teamwork, coding standards, and debugging skills—which interviewers value highly.

Q5. Was communication skill a factor in cracking the Microsoft interview?
Yes. Microsoft emphasizes clear explanation of solutions, structured thought process, and teamwork ability. Even if the code was correct, explaining the logic mattered equally.

Q6. How long did the IITian prepare for Microsoft?
On average, preparation took 6–12 months of focused practice on problem-solving, revising core subjects (OS, DBMS, OOPs, Networks), and refining soft skills.

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