DSA for backend interviews, without the grind.
Backend rounds test whether you reach for the right data structure and can state its cost. You do not need hundreds of puzzles. You need the core patterns and the habit of saying the complexity out loud.
Built with Nagendra Kumar, IIT Delhi graduate
· interviewed 300+ engineers
Readiness assessment
Know exactly where you stand in Data Structures & Algorithms.
- Overall readiness score out of 100
- Skill-wise breakdown across 7 areas
- Your gaps, ranked by priority
- An action plan and simple explanations for every miss
₹49
28 questions · 30 min · instant report
What interviewers check
Four things decide this round.
Hash maps and sets
O(1) lookups, counting, de-duplication and two-sum style problems.
Queues, stacks and heaps
BFS with deque, top-k with heapq, and when each fits.
Searching and sorting
Binary search on sorted data and the cost of sorting first.
Complexity
Stating time and space for every solution, and spotting accidental O(n²).
Try before you pay
One question.
See how you think.
This is the style of every question in the assessment: real situations, not trivia, with an explanation for each answer. The full test covers 28 questions across 7 skills.
You need the 3 most frequent words in a list of one million words. What is the cleanest efficient approach in Python?
Counter counts in one O(n) pass using a hash map, and most_common(k) uses a heap for the top k. Interviewers want the right data structure and the complexity said out loud.
Mistakes that cost offers
- Coding before choosing the data structure.
- Forgetting that `in` on a list is O(n) but O(1) on a set.
- Not stating complexity unless asked.
How to practise
Get fluent with hash maps, heaps, queues, two pointers and binary search, and always state time/space complexity.
- Solve 25 easy-medium problems grouped by pattern (hashing, two pointers, BFS, heap).
- Explain Big-O aloud for every solution you write.
- Use collections (deque, Counter, defaultdict) and heapq in real code.
Stop guessing what to study
Start free. Go further if you need to.
One-time prices. Add one-to-one guidance any time.
30-min test
Job Readiness Assessment
Free₹99one-time
One-time payment · Python / AI Backend Engineer
What you get
- Role-specific readiness assessment (28 questions, 30 min)
- Overall readiness score and skill-wise breakdown
- Strengths and skill gaps across 7 core areas
- Personalised assessment report with answer explanations
How it works
- 1 Unlock it at checkout
- 2 Take the 28-question test (30 min)
- 3 Get your report instantly
Best for: Candidates who want to know exactly where they stand.
Secure checkout · Full refund if not started
Test + 30-min session · Most chosen
Assessment + Personal Guidance
₹500₹599one-time
₹99 assessment + ₹500 for a 30-minute one-to-one session
What you get
- Everything in the ₹99 assessment
- One-to-one review of your assessment results
- Identify your highest-priority skill gaps
- Guidance on what to learn and practise next
- Personalised next-step action plan
How it works
- 1 Pay ₹599 securely
- 2 Take the test and get your report
- 3 Review it one-to-one on Google Meet
Best for: Candidates who want a clear improvement roadmap.
Mentoring is guidance to help you improve, not a job guarantee.
Secure checkout · Full refund if not started
60-min session
Personal Mentoring
₹999one-time
60-minute one-to-one session · No assessment required
What you get
- Deep-dive on your career and technical challenges
- Detailed review of your Python / backend skills and projects
- Interview preparation priorities and mock questions
- Written, personalised action plan after the session
How it works
- 1 Pay ₹999 securely
- 2 Pick a 60-minute slot
- 3 Meet on Google Meet, get a written plan
Best for: Candidates who already know what they need help with.
Mentoring is guidance to help you improve, not a job guarantee.
Secure checkout · Full refund if not started
Your mentor
Nagendra Kumar
IIT Delhi graduate · 10+ years
300+
engineers interviewed
50+
engineers hired
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Delhivery
FAQ
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