I was found by an interviewer at a university fair where we had a short talk.

The next day, I attended an open presentation by Microsoft, where they went in-depth about one of their technologies. I asked a lot of questions, trying to clarify missing bits and pieces.

After the presentation, I was invited to an interview the next day. It was a simple, one-question, 45-minute filter interview to determine if I was ready for the real thing.

Later, they flew me to another interview event where I had four consecutive interviews that lasted a total of five hours. I was mostly asked system design questions and was expected to discuss them with the interviewer. There were one to two simple programming questions to see the way I think.

Output the elements of a binary tree in zig-zag order.