Amazon Software Engineer Senior interview questions

Started with a recruiter phone call. Seemed like the recruiter was just asking questions for like a checklist they had to fill out. They couldn't answer even basic questions. Next was a take-home coding assignment on hackerrank. The questions were surprisingly difficult and very academic in nature. Recursion/Dynamic programming and the like. I didn't do very well and I turned it in, but Amazon never reached out to me either way after the fact, so just assumed I didn't get it.