FWIW, though I'm just one datapoint, if I'm going to have a "this isn't the day to day job" question thrown at me, I'd rather it be something more off the wall like this than most of the "do you remember this from your textbook/reference materials" style of trivia. Then I feel like approaching it from first principles is what's desired, and free to bounce ideas around, rather than being expected to remember the optimal log(n) "right" answer.