Amazon Software Engineer interview questions

Received phone call, I mentioned the call was quiet and kept breaking up. Interviewer tried his best to fix it, eventually called me back on a landline. I was asked some questions about what I did, and why I wanted to work for them -- general questions. Then I was asked some technical questions. Interviewer was polite and nice.

After applying online, I waited 30 days before being requested for an interview by an Amazon recruiter and I was set up for two phone interviews. The first interview went very well, although at times the questions were so vague that I felt like I would have to use divine power to come up with the answer that would match the question. For instance, rather than a straight forward 'what is unit testing?', I was instead asked 'what is a way to ensure that changes to a function will not have negative impact on other functions?' For me the answer is documentation - because that's how I write good conforming code that doesn't need unit testing in the first place, but go figure. Overall though, I was happy with the first interview, particularly as he made an effort to get to know me and I felt that I did well. The second interview was poor and the interviewer's style was frustrating. For example, 'how would you reverse a linked list?'. I provided a correct answer. 'What if there were no prev pointers?' I provided a correct answer. 'What if the list was so long that you can't use a memory buffer?' At that point I was annoyed... if the list is potentially that long then I would obviously put back the prev pointers. For me, an O(n^2) solution is not a solution at all. But that's not the game they want you to play. The worst part was when I gave a correct solution on how to find a common ancestor in a binary tree, but he thought it was wrong. I explained it again and it seems he understood, but then said 'are you sure that will work in all cases?' Yes, I said, I was very sure! I had drawn a binary tree diagram and tested enough cases to be absolutely positive it was correct. I even used the slowest, most reliable solution possible to avoid a repeat of the linked list annoyance that he had given me earlier. I had to keep convincing him before he eventually said 'well, let's move on'. Imagine how that felt. At that point I practically had to give up on the guy because it is annoying enough to get a couple of answers wrong but then also have your correct answers considered wrong as well! This did not leave a good impression on me, particularly knowing I would have to work with this guy. A few other questions seemed quite bizarre, but this report is long enough already. Unfortunately the recruiters also left an extremely poor impression - I would expect a phone call in the next 24 hours afterwards and then a follow up call after an official decision had been made. Instead I got a cut and paste message that wasn't even correct for my circumstances. Good luck Amazon. While I accept there may be some good people in your ranks, this experience doesn't make me want to become one of them.