Day 123 of 133
Privacy-preserving ML (federated, DP, on-device) + DSA review
When each is the right answer; cost in accuracy.
DSA · NeetCode Intervals
- Non Overlapping IntervalsDSA · Intervals
Interview questions to prep
- Do you sort by start or by end? Defend the choice based on the invariant you need.
- Walk through merge / overlap detection: what's your condition for 'overlapping'?
- How does complexity break down: O(n log n) sort + O(n) sweep — can you do better in any case?
ML System Design · Cross-cutting trade-offs
Interview questions to prep
- What levers do you pull when accuracy is great but latency misses the budget?
- Walk through where you'd add caching in a RAG + LLM pipeline to halve P99.
Interview questions to prep
- How would you design a cascade: cheap model first, expensive only when needed?
- What's the right verifier for the cheap model's output — and when does it dominate cost?
Interview questions to prep
- Walk through cold-start strategies for new users vs new items.
- Compare bandit-based exploration vs content-based bridges for cold start — when does each fit?
Interview questions to prep
- When would you reach for federated learning vs differential privacy vs on-device inference?
- What's the accuracy cost of DP-SGD at typical ε values, and how do you decide if it's acceptable?
MLOps · Privacy & security
Interview questions to prep
- How would you remove PII from training data without destroying signal?
- Compare hashing vs tokenization vs full redaction for PII fields — when does each fit?
Interview questions to prep
- Explain differential privacy in one minute — what does ε mean?
- How does DP-SGD differ from regular SGD, and what does it cost in accuracy?
Interview questions to prep
- When is federated learning the right choice over centralized training?
- What are the systems-side challenges in federated learning beyond the algorithm?
Interview questions to prep
- What is a model-extraction attack, and how do you mitigate it?
- How would you defend a public ML API from membership-inference attacks?
References & further reading