Amazon SDE 1 interview questions

I happened to Interview with Amazon India. They mostly concentrate on DS, algorithms and problem solving. I cleared my written test and was said will be having my face to face interviews. The first two rounds went very well. The interviewers were cool and were very much helpful in discussing the flaws,if any, of the algorithm and encouraging to write better code. After writing the code the discussion starts to check the code and verify and the candidate will be asked to rectify the bug or complexities. But the third round which I had, it went mostly like the interviewer asked the question and I answered with the approach and algorithm. I explained the algorithm and the way it works. That's it. There was no discussion on improving the correctness and neither the interviewer flawed my code/algo. After a quick process through that round, I was said, the round didn't go well. I was disappointed. It seems very well while the interview was going on and the interviewer was also had no objections. If the interviewer was not satisfied with the alog/code, the interviewer would, generally, ask the candidate to improve it or correct. I understand the interviewer was in hurry, but the way that round was conducted was not well.