[ytpete]

I'd still argue it's a bad sign if the candidate is stuck with nothing even compiling after 45 minutes. That's not a sign of the problem being complicated, that's a sign of the developer either (a) struggling to figure out dev environment basics, or (b) having a tendency to go way down one solution path without pausing for any simple gut checks / sanity tests of their work in progress.

In the latter case, is it possible for a developer to operate that way and still produce a great solution given more time? I suppose so - but in my experience, the people who are not in the habit of incrementally checking their work are virtually never strong developers.

There's also a time management question here. If a person knows they only have 45 minutes, that should create extra pressure to start testing earlier. Someone who still waits until time's almost up before checking anything is probably a fairly extreme case of this antipattern.