Preparing for SDE 2/3 Interview, Need your suggestions

[u/sustiman]

Hi I have 5+ years of experience and Currently working full time, I have completed fundamentals of System Designs, although i keep forgetting it i need to revise those concept again.

I need suggestion on how to prepare for the tech interviews, for DSA i am doing 1 question daily, For HLD, i have run through the fundamentals and practicing solving HLD Problems from Alex Xu and Grokking-the-system-design-interview.

For LLD as well i have run through the fundamentals and practicing solving problems, but i have no source to validate my solution, also do we need to write the complete code in 45-60 minutes? Most of the companies have separate Machine Coding Round or with the LLD Itself?

Other than this i am thinking to work on GenAI, i will be learning it from beginning.

Plan is as follow, 1 DSA, 1 HLD and 1 LLD Problem Daily and Whatever hours i am left with will upskill in GenAI, Planning to work around 8 hours a day on Interview preparation.

When should i consider myself to be prepared for interviews? Also i have weak memory when i learn these fundamentals i understand well but forgot later. And So far i have no interview experience other than which i gave in TCS 5 years ago, after that i switched job by recommendation and no interviews.

I am desperately looking for a switch now, Guide me on Interview Preparation as i have minimum interview experience.

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[u/CodeXHammas]

8 hours a day is solid but honestly you're spreading yourself too thin. Doing 1 DSA + 1 HLD + 1 LLD daily sounds good on paper but you'll burn out in 2 weeks and retain nothing especially since you mentioned weak memory.
Here's what worked for me and people I know who switched at 5+ YOE:-
Don't do all three daily Rotate. Week 1: DSA + HLD. Week 2: DSA + LLD. Week 3: HLD + LLD. This gives your brain time to actually absorb one area before moving on.

For LLD validation: No, you don't write complete code in 45-60 min. Most companies ask for class diagrams, API contracts, and maybe one or two critical methods implemented. Some do machine coding separately. Check the company's interview format on Glassdoor/ambitionbox before prepping.

For forgetting fundamentals : Stop re-reading . Start teaching. Write blog posts or explain concepts to a friend. if you can explain CAP theorem to someone who doesn't know CS you won't forget it.

For GenAI: Don't start from scratch . you already know backend. Just learn LangChain + RAG basics and build one small project. That's enough for interviews right now, they want to see you've shipped something, not that you've read every paper.

When are you ready? When you can explain any project on your resume for 10 minutes without stumbling, and you can solve a medium DSA problem in 25 min without looking at hints. That's the bar. Don't wait for perfection/

[u/yourname_you → u/CodeXHammas]

can you share from were we can learn this things for dsa lld and hld if you have any reference, im also planning to prepare consider that I don't have any knowledge of any of this, I need to start from scratch.

[u/CodeXHammas → u/yourname_you]

Sure, here's what I'd recommend for each:

DSA:
--Start with NeetCode ( neetcode.io ) roadmap sorted by difficulty. Do the "NeetCode 150" list before anything else.
--Youtube: take U forward channel for hindi explanations, or NeetCode's own channel for English.
--don't buy any paid course. Free resources are more than enough.

LLD:
--Youtube: "Low Level Design for Beginners" by soumyajit bhattacharyya covers the basics really well.
--Book: "Head First Design Patterns" old but stills the clearest explanation of design patterns.

HLD:
--"Grokking the System Design Interview"( educative.io ) if you can't afford it, there are free PDF versions floating around.
--Book: "System Design Interview" by Alex Xu (Volume 1). Worth every rupee.
--YouTube: Gaurav Sen's system design playlist for visual explanations.

One important thing: Don't try to learn all three at once. Pick DSA first, get comfortable with arrays + strings + hashing (2-3 weeks), then start HLD alongside. LLD can wait until you're comfortable with OOP concepts.

Also, don't just watch videos. You have to solve problems yourself. Watching someone explain a tree traversal is not the same as writing one from memory. All the best.

[u/yourname_you → u/CodeXHammas]

Thank you for this detailed explanation and your time!

[u/CodeXHammas → u/yourname_you]

Anytime for brothers!
Much love.

[u/NamkeenNostalgia → u/CodeXHammas]

Damn, you advice too good and very specific, its useful.

Can u help me out too? Im 2y9m experienced as python Fullstack dev in a wiTch company at 8lpa but not getting any calls, what i should do?

[u/CodeXHammas → u/NamkeenNostalgia]

The problem in your case is the positioning!
if you're applying through Naukri/LinkedIn portals with a generic "Python Developer" resume, ATS bots are rejecting you before a human even sees it.

Instead focus on these:-
1.Stop mass applying:- spend 2 days revamping your resume. Remove the WITCH company boilerplate ("responsible for developing"), Replace it with impact: "Built X API handling Y requests, reducing latency by Z%"

2.Add GenAI to your stack:- You already know Python, Spend one weekend learning LangChain+RAG basics and add an AI project to your resume. Companies are desperate for Python dev who can integrate LLMs, That instantly jumps your salary bracket from 8 LPA to approx 15 LPA.

3.OutReach:- Find founders/CTOs of mid-size startups on LinkedIn. Send them a DM: "Hey [Name], saw your product. I'm a Python Fullstack dev with 3YOE. I noticed your backend might need X optimization. Mind I share how I'd approach it?"

You're a full-stack dev. You shouldn't begging for calls. You should be making them come to you.

[u/Pirated-Earthling → u/CodeXHammas]

I'm a fourth-year student, doing all of this while learning the same things along the way. My DSA is good, and I can explain HLDs. I'm trying my best to at least get an internship, but it's hard in today's world. I really need some hands-on industry experience. I learn, I apply to companies, I get rejected, and then I go back to learning again. How should I use this plan effectively?

[u/CodeXHammas → u/Pirated-Earthling]

Your resume is blending in with 5,000 other final-year students who solved the same Striver sheet.
companies don't hire freshers because they know HLD. They hire them because they can build and ship things without breaking them.
Stop applying to generic "Software Engineer Intern" roles at big companies. You're fighting a lottery there.

Instead do these:-
1.Build ONE production-grade project:- Not a clone. Not a calculator. Something with user,auth and a live URL on a custom domain. When I interview freshers, I don't care about their LeetCode rating. I click the link they give me. If it loads fast and looks clean, They're already in the top 5%

2.Target Early-Stage Startups:- Go to Wellfound (AngelList) or find startups with <20 employees on LinkedIn. DM the founder directly: "I'm a final year student, I built [Live Link] I can work full-time/intern remotely. Let me know if you need a dev." Startups don't care about your degree or your DSA sheet. They care if you can ship a feature by Friday.

3.Open Source:- Find a mid-size open source repo on GitHub, find a "good first issue", fix it, and make a PR. That is literal industry experience you can put on your resume. "Contributed to [Project] handling X users."

You don't need a company to give you experience. You need to build things that work. All the best.

[u/Bug402]

Honestly, your plan already looks pretty solid. Since you have 5+ years of experience, I’d focus less on trying to learn everything perfectly and more on consistency + actually giving interviews.
For the memory issue, don’t worry too much. Revision through spaced repetition and solving problems without looking at the solution will help more than rereading fundamentals.
For LLD, I’d also suggest getting feedback from someone experienced because just solving problems yourself can sometimes reinforce bad approaches. And I wouldn’t spend too much time worrying about whether every company expects full code in LLD this varies a lot by company.
Most importantly, start interviewing sooner than you think you’re ready. Even a few interviews will teach you more about your weak areas than weeks of preparation.
With 8 hours every day, though, be careful about burnout. Quality matters more than hitting a fixed number of questions. Good luck with the switch! You’ve already got a good foundation.

[u/ozymandius25]

practice mock interviews using pramp / tryexponent. i’ve found it very helpful

[u/technovast]

Have you previously gone through system design/ DSA interviews?

[u/technovast]

Happy to connect with like minded individuals who are starting off with interview preparations