Amazon Internship interview questions

This year was less dragged out than the year prior however, I think most people get to the final interview no problem. First year I applied, I got almost no cases on the technical problems and somehow still managed to get the final interview. The second time around, I got most if not all but some edge cases and got the final interview. I dont know who chooses who advances. Another thing to note as well is I was never contacted by a recruiter, it was done all over automated email until the final interview.