I had one phone interview over Skype with a recruiter where I was asked about my past projects and experience. I was also asked to solve a little puzzle question.

It felt strange and irrelevant to my job application. I expected another round of Skype interviews, but instead I was invited for an onsite interview.

I had four technical interviews onsite, all of them about 45 minutes. All had a similar process:

You meet the interviewer, who talks about himself and his job role. Then you talk about yourself. At the end, you get a coding problem that you have to write on the whiteboard.

Most of the questions were from the "Cracking the Coding Interview" book.

I received a question about how to determine the number of ones (1) in a huge bitmask (10^7 bits) using a processor's machine language. A correct answer was not expected.