I was contacted by a recruiter and took online screening which was a moderately hard tree problem. It was hard because the test was on hacker rank platform and you need to get your code compiled and all the test cases must pass. After online test, they called me for onsite where they grilled me on both algorithms and leadership skills. I guess I was not prepared well for leadership skills test because I did their algorithm questions well and still didn't get an offer. One thing I felt is that compared to other interviewers I met when I appeared for other companies, some of the Amazon interviewers were not that friendly.