This problem outlaws the obvious division trick, forcing the prefix/suffix-product insight. Interviewers look for computing left and right products in two passes with O(1) extra space. 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.
This problem outlaws the obvious division trick, forcing the prefix/suffix-product insight. Interviewers look for computing left and right products in two passes with O(1) extra space. 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.
