Microsoft Software Development Engineer In Test SDET interview questions

I had three interviews after flying out to Seattle. 1) The first interview was a coding question in which I was asked a puzzle. The question was you have 100 doors in a row that are all initially closed. you make 100 passes by the doors starting with the first door every time. the first time through you visit every door and toggle the door (if the door is closed, you open it, if its open, you close it). the second time you only visit every 2nd door (door #2, #4, #6). the third time, every 3rd door (door #3, #6, #9), etc, until you only visit the 100th door. I was told I could answer the question using code and so I did by brute force. I coded it very well and the interviewer guided me through it. 2) The second interview was a regular Q & A situation in which I was asked the usual questions about problems I've faced how I solved them etc. 3) The third interview was over lunch and I was asked to test a number of things such as a PC, a ketchup packet. I didn't do so well in this one.

One on campus interview as a general screener, and then 5 onsite interviews with the teams interested in my profile. Onsite interviews happen in one day from morning to evening, approx an hour each.