Microsoft Senior Developer interview questions

As a college student, Microsoft first came to my Campus to give me an interview, where they asked me a challenging programming logic question. I passed that interview, and they flew me to Seattle for an on-site interview. Over the course of a day, I had 4 interviews that were much like my on campus interview. At each interview, I was asked a technical question. From what I heard, it seemed that only about one out of every four people who are flown to Seattle will receive an offer.