[fencepost]

I'm sure I could do it in something pseudocodish, but it'd probably take an embarrassing amount of time. Honestly I could probably do almost as good a job of implementing quicksort, at least in a naive version based on the stack.

Seems to me that what interviewers should be looking for is not savants who can whack out particular odd bits of code but developers who can look up some things to use as reference as they go and most important who know how to determine what it is that they need. Proper evaluation and decision making is at least as important as actually writing the code, because those are the skills that can keep you from writing the wrong code.