I was a part of the campus recruitment process. There was a general aptitude test, which is simple if you've practiced enough. This was followed by an interview, where they ask you about things in general. Following this, there's an interview where they test your logical thinking abilities and give you a few puzzles to solve. Some of them require you to think out of the box. The final round is also a general HR-like round. The whole process for over by late evening.