Two rounds of the interviews. Two people each rounds. Then, I would have the superday interview. This round would be with four managing directors. Overall, the interview was not hard, since I've prepared all the questions necessary for this.

Keep in mind this was only a first round interview for an off-cycle position, and I was not super prepared at this time (a couple years ago). However, I found the interview very strange, as I got an email at 10am, asking for a phone call at noon. Interviewer was super inpersonal, hardly asked any resume, education, or experience related questions, then jumped right into some basic technicals. the whole thing was only 15-20 minutes, and while most of the technicals were easy, a couple more difficult ones tripped me up.