Amazon Software Engineer interview questions

Phone interview lasted about an hour. Interviewer was prepared. He was polite. We talked about some of my previous projects and used that to discuss issues/solutions to capacity/scaling and reduncancy. Seemed like more of a 'chat' than specific questions and answers. There were some questions about arrays and linked lists. One that I remember was how to handle a sparse array if memory was limited. Interviewer asked questions to make sure I knew what I was talking about, but he was certainly not trying to trick me. He left some time for me to ask questions. I wanted to know about day-to-day life. They are focused on results and let you manage your time - very flexible on work from home. They provide a platform of your choice (Windows, Mac, Linux). Overall, the interviewer was someone I would like to have a beer with, and the company is a place I would like to work (hope they are reading this :-)

1, why Amazon? 2, introduce your projects 3. power of a number 4. Polymorphism?