Amazon Software Development Engineer interview questions

They saw my profile from LinkedIn.com and contacted me first. They suggested me to interview and adjusted schedule. I didn't have any phone interview. They called a few times, however, those were a simple check for my experience, education, etc. and they provide interview prep tips. There were four interviewers, each of them took about 50 minutes, and the all the interview took 4 hours. First interviewer asked about my experience and ask simple algorithm, data structure, etc. Second interviewer asked to solve 2 quiz. Third interviewer asked some object-oriented topic. Forth interviewer asked to design some system. After a week, they offered.