I work in Amazon Capetown office.
In Microsoft it was mainly natural language processing. In amazon I've been here for 2 months and I learned a lot about Bash, Git, Distributed Systems and synchronization between them, BigData, NoSQL databases ... and much more.
The interview didn't include any of this, it was just basic problem solving and data structure questions.
It's very easy to learn technologies, don't bother doing that before graduating.