Amazon Software Development Engineer interview questions

Started with two phone interviews, mostly algorithmic questions plus one design question. Then an onsite interview with 4 member of the team I would join in addition to one outsider. I did well on the interviews. For a couple of them I finished the main question quickly and the interviewer had to come up with additional questions for the remaining time. However, later the recruiter called me and asked about my visa sponsorship requirement and export control license (I needed both). Finally I was told that Amazon has recently decided not to hire nationals of certain countries (including Iran) because it provides cloud services to the government. So unfortunately I couldn't get the job.

After an introduction we talked about projects. 1st interviewer asked to check if a string is a substring of another string. Second interviewer asked to reverse a linked list