Apple Software Engineer interview questions

I applied the internship during the career fair in our university and got an on-campus interview on the next day. The interviewer is really nice. We started with some basic programming problems. I was asked to write code on the board. Then we discussed something about GPU and deep learning since the interviewer works for Siri Team. But I don't have much knowledge about GPU, so I failed here. Anyway, I still feel really happy to get this opportunity, which is actually the first career interview in my life.