Comment by chaboud

Note how I structure my problem solving questions to be progressive and adjustable, both up and down. This gives me room to simplify and get the candidate to a place where they can show me something (candidates who truly come up goose eggs on everything functional but still show solid fundamentals may be showing that the interview is for the wrong job family). It also means that it is virtually impossible to get all the way to "the end" and "finish" the problem, as I leave room for extension and modification. I had one question that I thought was long enough, and, of maybe ~120 interviews with it, exactly two people dunked on it, one writing out code for solutions with and without libraries. That guy was a complete jerk, and I wasn't at all surprised when the entire panel came back not-inclined.

My first boss (a CTO at a start-up) drilled this into us. What you know is far less valuable than how you learn/think and how you function on a team.