I got 2 back-to-back 45 minutes interviews. I think I was a bit too slow on answering the questions, and I got completely flustered when asked if I had any questions at the end of the first interview (don't do that, prepare questions, such what the interviewer works on and how he likes Google etc.).
I did sign an NDA, so I won't say what the questions were, though they did cover BSTs, binary search, finding intersection. I also explained how mergesort works (and I didn't do it as naturally as I should have).