Implement binary search and its variants (first/last occurrence, search in rotated array).
Binary search is simple to explain and notoriously easy to botch (off-by-one, infinite loops). Interviewers look for a correct template plus the variants (boundaries, rotated arrays) that show up constantly. The answer follows.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
Binary search is simple to explain and notoriously easy to botch (off-by-one, infinite loops). Interviewers look for a correct template plus the variants (boundaries, rotated arrays) that show up constantly. The answer follows.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
