Several phone calls to go to the final round. The phone calls consists of mathematical, probabilistic brain teasers which was not that hard for a mathematics major. Final round was to harsh for me, strong mentality is required

Lots of expectation/probability questions. Make sure to study game-theory type question that involves expectations. Specific concepts in stochastic processes don't seem that important. The first two were relatively easy. Just make sure to ask a question if there is any uncertainty

very fun a lot of interesting problems. The person which was managing the interview process was easily aproachable and really nice to talk to. Also interviewers seemed really interested in the problems given and gave me a lot of chances to talk about them