I was invited for Onsite after clearing the OA. Got all questions from the Amazon OA Questions leetcode post.

Round 1: LP Questions +
Graph question similar to number of hops to reach a person on linkedIn through your network (freinds of freinds).
Follow up on: If weights are added to the path, how would you solve it.
Round 2 : LP Questions + Design Boggle Game
Round 3: LP Questions + Design chat server
Round 4: LP Questions. In Depth Resume grilling. In-Depth on system design related to work.
Round 5: LP Question + Simple Java Abstraction Question.

Answered all question but still got rejected. I guess its all based on Luck. Quite a long tiring day. Be prepared with LP, lot of questions on current work and implementations.