Phone interview was about my experience with C++. In person interview, was a whiteboard interview coding a data structure of my choice. Make sure to study, in particular study data structures. I did a stack with using a linked list in Java. Before that I was presented with a coding joke problem. It was a comic in which robots were killing humans and it showed some incorrect code. The problem was the if statement was
"= " instead of "==" which made the robots start killing the humans.
Next general and behavior computer science questions. Talked about a bit on my resume which they will have at hand. Mentioned my experience as a tutor and operating systems class as they didn't ask this and I thought it would be valuable information . I showed a lot of enthusiasm to a project about frequencies and they really liked that. In the end, I think that's what landed me the job offer.
Aside: Make sure you have a security clearance and mention it if you do. This helps with them favoring you as you can start on the job quicker.