Jatin Kaushal
🔗 Try the free version here
(20 problems, open-source, no signup. If the format clicks, come back for the full 100.)
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Dsa-meets-design / pro
100 machine coding + LLD problems with full editorials. Real interview questions from Amazon, Flipkart, Razorpay, PhonePe, Meesho, Swiggy, Uber, Ola, Microsoft, Google.
(Have a quick look at here - demo video)
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THE MOMENT THAT DECIDES YOUR INTERVIEW
Your interviewer says: "You have 60 minutes. Start."
You know the problem. Some variant of Splitwise. You've read the LeetCode thread, bookmarked the GitHub list, watched the YouTube breakdown. You know the patterns.
You start coding.
45 minutes in, Part 2 drops: "Now add group expenses with custom splits."
Your design can't hold it. You'd need to rewrite three classes. You have 15 minutes left.
You don't get the offer.
That moment - where a design decision made in minute 5 costs you everything by minute 45 - is the junction. It's the one thing every machine coding round tests, and almost no
prep resource teaches.
This repo fixes that.
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WHY THIS EXISTS
LeetCode-style GitHub lists give you questions with no structure, no editorials, no way to know if your solution survives Part 2.
YouTube playlists teach patterns in theory. They don't show you where the theory breaks in a timed interview.
My free repo (60+ stars, 17 forks, 2 PRs) introduced the format. 20 problems, open-source, people liked it enough to fork.
This is the Pro version. 5x the content. Full editorials. Company tracks. Dashboard. The complete system.
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WHAT'S INSIDE
🔴 100 problems from real interviews — tagged by company, pattern, and tier. No recycled "Design Parking Lot" filler.
🎯 3 difficulty modes per problem:
- Interview — blank slate, like the real thing
- Guided — interface shells and hints
- Learning — full structure with TODOs so you focus on logic
📖 Dual-view editorials for every problem:
- LLD view — which patterns fit, which don't, what breaks under extension
- Machine Coding view — implementation order, time splits, fast paths
- The Junction — where your design decision costs or saves 15 minutes of coding. The section you won't find anywhere else.
🏢 9 company-specific tracks — curated problem order, what each company evaluates in Part 1 vs Part 2, and a "solve these 5 and you're ready" shortlist per company.
🧩 10 design pattern primers — Strategy, Observer, State, Singleton, Factory, Chain of Responsibility, Command, Decorator, Proxy, Builder. Each tied to a drill on a real
problem.
💻 Local dashboard (React + Express) — in-browser editor, test runner with per-part pass/fail inline, filters by tier / company / pattern. Clone and npm run dev. No server, no
login, no telemetry.
📅 6-week prep playbook — Week 1 LLD foundations → Week 2 machine coding speed → Week 3 the junction → Week 4 company focus → Week 5 gauntlet → Week 6 mocks.
📋 Cheat sheets — pattern-selection flowchart, time-split templates for 45/60/90 min rounds, top-20 candidate mistakes, interview-day checklist.
🤖 AI review prompts — paste your solution into Claude (free at claude.ai) and get scored against a 50-point rubric. Covers design, code, and junction decisions.
Languages: C++, Java, Python. All in every problem.
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WHO THIS IS FOR
Engineers with 1-5 years of experience targeting Indian product companies who:
✅ Can write code but freeze when told "design it first"
✅ Got rejected after Part 1 because adding Part 2 meant rewriting everything
✅ Have done DSA but were blindsided by a machine coding round
✅ Want to stop collecting resources and start practicing the skill that actually gets tested
Not a fit if you haven't written a class before. Do a DSA course first, come back later.
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HOW ACCESS WORKS
1. Pay on Topmate — enter your GitHub username when prompted during checkout
2. You'll get a GitHub invite to the private repo within minutes
3. Accept the invite, clone the repo, run npm install && npm run dev and you're in
No login accounts. No DRM. No subscription. One-time purchase. Yours forever, including every future update.
Didn't get an invite? Check github.com/notifications. If it's been more than 15 minutes, DM me on LinkedIn or reply to your Topmate confirmation email.
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MY COMMITMENT
✅ New problems. Got asked something not in the set? File it in the repo — I'll add it with a full editorial.
✅ More languages on request. C++, Java, Python & Javascript today. Go, Rust, TypeScript - DM me if your target company needs one.
✅ Active maintenance. Dashboard bugs, test issues, typos — filed and fixed fast.
✅ Direct access to me. I built every problem. I read every feedback. This isn't a course from a team you'll never talk to.
Questions before buying? DM me on LinkedIn. I reply within a day.