Google (Senior) Software Engineer interview questions

Went onsite with Mountain View campus for position in google cloud division. Total 5 interviewers. Not sure how they selected the interviewers - end up 3 interviewers asking distributed system questions. One scheduled interviewer did not show up, so a replacement guy showed up with very little preparation. Another interviewer came from hardware group which is surprising (I am not a hardware guy, and the interviewer did not get to any kernel level question as well). They seem to have quite different background as I do, making the interview process somewhat out of synergy. It became an awkward process.

Round 1: a recruiter calls you. They will ask you a few simple questions. Things such as "what's faster, quicksort or bubblesort". If you answer enough of these correctly, you get to the next round. If you fail here: stop moaning, go away and go improve yourself, there is no way you would have passed the later stages anyway. Round 2: an engineer will call you, and interview you for 45 minutes. Only the "best" interviewers get to do what we call "first phone screens" because that's where the most people get kicked out. Round 3: exactly the same as round 2, but with a different engineer. From the interviewer's perspective, second phone screens are infinitely better than first phone screens, because the totally incompetent have been weeded out already. Round4: onsite interviews! you will have 3 interviews of 45 minutes, lunch, and 2 more interviews. These are basically the same as phone screens, but you get to see the interviewers face to face.