The strongest candidate I ever voted no on solved the problem in eleven minutes. Clean. Optimal. Caught the edge case I normally have to hint at twice.
Then I opened my notes to write the scorecard and found one line: "Solved it. I have no idea how."
That is the short version of why strong engineers fail coding interviews. Not because they can't code. Because nothing they did survived the trip from the room to the scorecard. The interview is not the thing being graded. The document I write forty minutes later is the thing being graded, and you are not in the room when it gets read.
TL;DR
Strong engineers fail coding interviews mostly on signal density, not correctness. A silent correct answer scores lower than a narrated near-miss.
