Since the placement season is starting soon, here is a prioritized compilation of the minimum knowledge required to clear most software interviews.
The word minimum is used deliberately — this guide only covers essentials, not everything.
I have written it in priority order so the things on top are more important than those at the bottom. Start learning from top to bottom.
Have at least one good project on your resume. The tech stack doesn’t matter, but it should be worth discussing for at least 15 minutes.
Prepare all technologies mentioned in your resume. If you’re not confident about something, remove it.
DSA is asked in almost every company. If you can solve at least LeetCode medium problems without hints, you can clear most companies’ DSA rounds.
If you haven’t done DSA yet, you can speed-run the InterviewBit problem set (~270 questions): InterviewBit Programming Course
Learn OOP concepts thoroughly: class, object, interface, inheritance, compile-time & runtime polymorphism.
Even if your interviews don’t have dedicated HLD rounds, knowing the basics will help in explaining your projects and CS questions.
Sufficient resource: System Design Handbook
Processes, threads, multithreading, CPU Scheduling, etc.
Learn from: techTFQ YouTube Channel
Practice on: HackerRank SQL Domain
After OOPs, learn SOLID and key patterns: Singleton, Factory, Observer, Adapter, etc.
Practice LLD questions like Parking Lot, Vending Machine, BookMyShow.
Focus on TCP, OSI Model, and UDP. That’s usually enough for interviews.
This knowledge is sufficient to clear most HLD rounds.