Amazon Software Development Engineer II interview questions

THE WORST INTERVIEW I EVER HAD. I applied for AWS OpsWorks (Berlin). First phone interview was quite simple. Just interviewer asked 2 algorithmic questions relevant to searching and stack. After 1 day recruiter sent me an email to have the setup the second interview round. Second phone interview was a behavioral interview and ended up with an algorithmic question. After 2 days I got an email about setting up an onsite interview. I was asked to propose some days in the next 2 weeks when I can be available whole the day there. I answered them: Every day in next 2 weeks "EXCEPT THURSDAYS" I can be available. After a day she sent me a list of 7 interviews, all were planned exactly for the next "Thursday"!!!! Was really disappointing, I had to cancel many meetings to free my Thursday. She just apologized me for inconvenient! The other point was about the number of interviews, 7??? Anyway I confirmed the date with her. First onsite interview was a technical one with very simple questions about OO design. Second interview was about system design and again very basic OO questions. Then we went for lunch with one of the AWS engineers. He was very kind, actually lunch was not a part of interview. third interview was with one of the software development managers from Amazon Machine learning team! He was so kind and asked couple of behavioral questions. Believe it or not instead of the forth interview I just faced with the Recruiting manager! She told me there was a problem in interview setup and those "4" interviews that you had today are enough (She even did not know I had 3 interviews rather than 4) and apologized again for the inconvenient bla bla bla.... After 10 days I got a phone call from the HR manager first of all she apologized for the third time that could not contact me in the previous week and she tried to tell me that I am rejected :)) I was shocked that how I could be rejected after answering well to all the technical questions and behavioral questions!