Amazon Software Development Engineer, interview questions

Online test of 5 coding questions(easy) for screening to 1:1 interview round. I have heard there is phone interview as well for some people. I didn't have phone interview. There were 5 round of 1:1 interviews in a single day in their office. They were mainly concerned about our coding skills - covering all testcases, etc..

I had two telephonic interviews for about 45 mins each. The focus of the interviews was data structures, algorithms, oo design concepts and basic coding. Once I cleared the telephonic interviews, I was called in for an onsite interview which again focused on the same areas but little more in depth. I had 4 45 min 1:1 technical interviews. I had to work on one problem in each of the rounds. Problems focused on random numbers, trees and problem solving. I had 1 hour of lunch interview with the hiring manager. He explained about the group, work culture. He asked me to talk about my research and asked one technical question at the end. I liked the people. Casual work culture.