Amazon Software Engineer I interview questions

First, I get contact with Amazon recruiter and then followed by two phone interviews which lasted for 1 hr of each. On-site interview took place two weeks later after phone interview, which lasts for a whole day, seeing 6 employers in 5 groups (there were two Amanzonians forming a single group). Each group took 1-hr meeting, asking for technical and non-technical questions. Questions include algorithms, design patterns, behavior questions, brain teasers.

I uploaded my resume on their website and got an email within a week to schedule an interview. Due to personal reasons, I had to reschedule a couple of times. Then on the day of the interview, I got a call exactly at the scheduled time. Interview was fine, but the interviewer was not clear with the questions himself. This got me a bit irritated.