Recently I had Amazon Onsite for the SDE2 position. I'm still waiting for the results but wanted to share my overall experiece:

Round 1: Started with LP and headed to the coding question. More likely to design an unbounded Set where each entry has an expiration after the current system time. I spent a bit more time trying to understand the question more which at the end seems like TreeMap problem. Interviewer seemed okay with my solution but didn't able to complete all the API and shared my thought process.

Round 2: Again started with LP question and then system scaling for the parking lot ticketing system. Interviewer kept changing the requirement how to handle the ticketing system and added lots of use cases. Didn't perform well in this section, also I could have asked too many question to clarify the ambiguities better.

Round 3: LP + question related to trapping water in 2D.. able to come up with DFS solution and not able to optimized it. However interviewer seemed happy with my solution

Round 4: LP + related to https://leetcode.com/problems/meeting-rooms-ii/ but lots of additional use cases. Able to come up with the optimal solution however not able to complete the whole coding.