My guess is that he wanted to see if you could think your way towards some kind of algorithmic approach. I think his biggest mistake was not moving on to someth

My guess is that he wanted to see if you could think your way towards some kind of algorithmic approach. I think his biggest mistake was not moving on to something else after a minute or two. I've used these sorts of questions in interviews before, but usually just as a small part of the overall interview. I prefer to ask questions that relate more to what we're actually doing (a real project, a real technical challenge we recently faced, etc.) I wonder if FB has formal standards for its interview process, or if they just grab someone and say "Hey, go interview this guy."