Back-to-back 45-minute interviews for the first round. Some time was spent on behavioral questions, but the case was clearly the only thing of interest to the interviewers. For the cases, they seemed to want me to go on a very specific route (they had several charts that only made sense if they were presented in a certain order). Because the interviewers offered no direction beyond stating the initial problem, it took some trial and error to get on the right track.