Comment by fishnchips

> if they actually meant for you to recurse down and swap

While only the person asking this question knows for sure I'd assume that was the intention.

It's not a _terrible_ question - it's just a recursive equivalent of FizzBuzz. You would treat this as a way of making a (good) candidate gain some confidence. And that alone is extremely important since the more at ease the candidate is the better the signal that you're getting. What I was trying to say there was that if I asked that as a warm-up and didn't get a satisfactory response very very soon I'd realise that your man has no clue about recursion and would move to the main question, choosing one that does not involve it. It would be something easier than I'd ask otherwise and would be closer to real-life scenarios - like first solving a simple problem, then parallelising the solution and correctly managing concurrent access.