Amazon Data Science interview questions

I didn't have to get through HR interview(s), I was directly interviewed by a tech personnel (he was the hiring manager). That was pretty good from my viewpoint and I'd give a big plus for that. He had given some details about the job, then he asked about my professional experience as a DS, and after that I got a few exam-questions. The questions were rather algorithm-oriented than statistics or data science related, but they were still simple enough for me to know the answer (see below). On the next day I've seen on the dashboard, that I'm out of the race, but haven't got any feedback (not even a mail) on what went wrong or what is missing from my skill set. Lack of feedback after a 1-to-1 interview is a big minus I think.