Three rounds total. First was a set of puzzles and logic games, around 20 questions. This round also had a set of debugging questions but it was basic, like finding what the error in the code was and stuff. Second round were actual data structure questions, but pretty straightforward if you've learned CTCI. Final round was a phone interview and I think its up to chance here; my interviewer spent most of the time asking about my resume and projects and only left a little time for his actual coding question.