Q&A Bank¶
Short, defensible interview answers - the kind an interviewer would accept in a conceptual round or as a follow-up. This is not a LeetCode problem list (that's Mock Interview Questions); it's the "explain X / why X vs Y" bank that pairs with the Fundamentals concept notes.
How to use¶
- Drill actively: read the question, answer out loud in 2-5 sentences before reading the answer. Interviewers grade clarity and trade-off reasoning, not word-for-word recall.
- Each answer is interview-length on purpose. For the deeper "why," follow the link to the matching Fundamentals note at the top of each file.
- Use the Follow-ups under each answer to simulate how a real interviewer pushes deeper.
- Rapid-fire (Rapid-Fire Q&A) is for one-line definitions - warm-up or last-minute review.
Answer format¶
Every question follows the same shape:
Q. The question. Answer first - 2-5 sentences, trade-off framed. Follow-ups: the natural next probes.
Difficulty·Companies
Legend¶
Difficulty: Easy (entry level) · Med (standard entry-to-mid) · Hard (mid / senior depth).
Companies: directional tags for where a question commonly appears - MAANG (broadly across big
tech), or a specific culture cue like Amazon, Meta, Google, Startups (Indian unicorns /
fintech). These are indicative, not guarantees - no invented frequencies.
Files¶
| File | Topic | ~Q | Pairs with |
|---|---|---|---|
| Operating Systems Q&A | processes, threads, memory, scheduling | 18 | Operating Systems |
| Concurrency Q&A | locks, races, deadlock, async, GIL | 22 | Concurrency & Parallelism |
| Networking Q&A | TCP/UDP, HTTP, TLS, DNS | 18 | Networking |
| Databases Q&A | ACID, isolation, indexing, SQL/NoSQL | 22 | Database Internals |
| Hashing Q&A | hash tables, consistent hashing, bloom | 12 | Hashing |
| Caching Q&A | strategies, eviction, invalidation | 12 | Caching |
| Security Q&A | authN/authZ, tokens, attacks | 13 | Security Fundamentals |
| OOP & Design Q&A | OOP pillars, SOLID, patterns | 17 | OOP & Language Concepts |
| System Design Concepts Q&A | CAP, LB, queues, sharding, estimation | 22 | System Design Guide |
| Python Language Q&A | GIL, mutability, generators, decorators | 13 | Memory & Runtime |
| Rapid-Fire Q&A | 1-line "define X" drills | 25 | all of the above |
Target: ~200 Q&A total across the bank.