How do k-NN and Naive Bayes work, and what are their assumptions and tradeoffs?

Two simple classifiers that keep showing up in interviews because they check whether you grasp assumptions and tradeoffs, not just sklearn calls. What matters is k-NN's laziness and curse of dimensionality against Naive Bayes' independence assumption. Here is the answer.

Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.