Amazon Software Development Engineer interview questions

the whole interview was easier than i thought, i was very nervous though, i didnt do good in my first interview, i didnt even had time to finish the programming question, the guy told me you are on right track but we are out of time :( my second interview was easier, it was mostly OOP design. but yesterday i got an email that they want 3rd interview

I applied for some job post on amazon.com career site. And i was contacted to go for my first interview in my university's career center. On that evening, I was told that i will be proceeding to the 2nd round, which is another 3 interviews two days later. All 4 of the interviews are technical based and 45 minutes each. I got an email that they would like to make me an offer the day after the 2nd round.