After meeting with the representatives at a career fair and applying for an on-campus interview, I was offered such an interview.

The Interviewer was running a bit late so we went directly to the brain teasers. He asked me to solve 3 small problems, I had a paper and a pen and I had to think aloud. He was not very helpful until it became obvious that I was out of inspiration (often the solution was right before my nose...)

Then I got to ask questions about the company, the interviewer was friendly and that went well.

How many ways are there to climb stairs if you can either walk up one step or two steps each time.