Amazon Software Developer interview questions

Group interview (university graduates). The candidates were assigned to groups of 2-3 people. Every group is to complete a project which has 3 kind-of-independent subproblem. It's suggested that each candidate responsible for one subproblem. It's more like a individual project, since everybody's input/output file is independent from his teammates'. The problem is not hard if familiar with OOP and java, and time is sufficient. It's important to understand the requirement of all 3 parts of the problem to get better insight of your own part.

Initially contacted by headhunter. Did 2 phone interviews, one basic HR, another one with a very nice programmer, followed by a programming challenge to send in. Then I was asked for an on-site interview in Vancouver. The on-site was really tough, 6 interviews back to back with no break (even lunch is a conversation with your potential manager and one of the IT managers higher-up).