Having been through this I can give a little insight. All the questions are from the interviewer. There is no MS book of interview questions. Each person ask

Having been through this I can give a little insight. All the questions are from the interviewer. There is no MS book of interview questions. Each person asks whatever they feel like at the time. While they seem like pointless questions for some jobs, this list is a conglomeration of questions for the three types of positions (Dev, Test and PM). The questions are made to be very difficult because the interviewee is supposed to struggle and have to verbalize what he/she is thinking. If the questions are less strange there is the chance that a candidate will have seen them before and know how to solve them off the top of their head. That's only useful for weeding out people who can't program at all. The verbal communication is just as important as actually solving the problem correctly. Microsoft has a pretty high confidence in it's mentoring system, it believes that teaching the actual code is much easier than teaching how to think systematically. I was given questions that took me > 6 hours to fully complete when I went home and did them. There is no way the interviewers actually wanted all the code, just a discussion. Some of the "Gotcha" questions are from earlier in Microsoft's hiring practices, so take these lists with a grain of salt. Though they are wicked fun to try to solve them all. HR at MS is very good at their job. They keep track of everything about who talked to whom.