Remove the Nth node from the end of a linked list in one pass.
The two-pass length-then-delete solution works, but the interview asks for a single pass: a gap of N between two pointers, plus a dummy head that makes deleting the real head come out for free. Here is the clean answer.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
The two-pass length-then-delete solution works, but the interview asks for a single pass: a gap of N between two pointers, plus a dummy head that makes deleting the real head come out for free. Here is the clean answer.
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.
