Well, I can only say my interview experience was pretty bad and unprofessional with those guys. After I cracked the phone screening, they invited me for the onsite interview. The interviewers were pretty rude, trying so hard to find bugs in my code, not helpful at all, and it eventually looked like they had to accept my solutions unwillingly. I think I did a pretty good job, but it looks like that wasn't enough, interestingly, to get the job. I noticed they had already determined who to hire because the job was already closed before my interview even started. So why waste my time? Really, Microsoft, why? If you guys would tell me the reason honestly, I would be like, 'OK,' and understand that. I'm pretty sure I would reject their offer if I had received one, since I wouldn't like to work with such guys...

Code to find the height of the binary tree.