I had given my resume to representatives of the company at my school's career fair, and got an email back about a week later saying they wanted to schedule a phone interview. I talked with the interviewer and he asked common algorithms and data structures questions. He also asked for me to explain eigenvalues (i.e. explain something fairly technical so someone with less background can understand it.) The next week, I received an email asking me to fly out to interview at the headquarters. I flew out, and was interviewed by three different people in the morning, then went out to lunch with some more employees, and then was taken back to have a demonstration of their software. The first interviewer focused on typical interview questions (i.e. why do you want to work here?). The second interviewer dealt with algorithms and coding problems. The third interviewer asked a lot of questions dealing with IT and computer support. If you're asked to leave after the demonstration, you won't get hired.