Applied online through their site and heard back two days later wanting to schedule a call. My interview was basically a phone screen. Pretty technical and detailed for a phone screen, I was caught off guard a bit. The call was about an hour and a half long.

Be ready to answer questions quickly, they really don't take time for small talk. There were about 50 questions in total. There were zero fit questions, almost all programming questions

Extremely minute details of the c language. Lots of structs, pointers, overloaded while loops where you had to keep track of multiple variables. Also a lot of types and printf statements. Overall not a very good test of any programming ability as the answers were only to be computed using pen and paper.