I definitely wouldn't want to work on your team, if that's how you interpret such an answer. Perfect interview then -- we've both eliminated the other as a viable employee/employer, so that's a win and we got there from just 1 trivial coding question. There's so much more to say here, but this is no longer timely, plus this isn't great forum for such discussion.

FWIW I have never been asked this question or similar, but since it's so famous I do have my own answer at the ready, which is just slightly more complex than the naive solution, but still well within the realm of production-worthy (maintainable, testable, readable) code. We don't really ever see any discussion of such because of course it isn't "interesting".