Interviewed on campus, questions were very easy all technical based. Received an invitation to interview on-site. During the on-site interview, I was asked some simple programming questions in the first interview. I then was asked some math questions the next hour. The questions were not difficult, but the interviewer wanted me to solve the problem his way. I was unable to, but solved it a different way. This was not good enough and he became difficult to work with. He was in some sort of leadership position with the company so I knew I wouldn't be getting the job, so I really stopped trying. After that there were three more hour long interviews, including one in which I was instructed I had ten minutes to come up with material and give a presentation on something I knew about that would last 15 minutes.