I just went through OA. The position I applied for was SDE II, so the OA consists of 2 Algorithm questions, some System Design questions, some SDE workstyle questions and some personality questions. Overall the experience was positive and I got the message from the recruiter that I passed the OA and pending next steps:

The first question I got was: https://leetcode.com/discuss/interview-question/1469039/Amazon-OA-CountMaximumTeams/1086834, a very classic Sliding window technique question.

The second question I got was: https://leetcode.com/discuss/interview-question/1501685/AMAZON-or-OA-or-Find-Valid-Discount-Coupons, a very traditional string processing question, you could either do 2 pointer or user a stack.

Both questions were not hard and I finished both questions within 30 min with all test cases passed, and I was debating if I should submit it or sit a little longer before I submit it as I don't want them to question how he answered those questions in such a short time, but I mean they are not hard at all....

I paid extra attention on explaing my code with documatation and in code comments with very descriptive variable names, and it did not ask me time and space complexity as in the mock OA which was interesting as I was looking everywhere to try to find the place where I am supposed to provide my approach and complexity of the algorithm!

Wish me luck on the upcming rounds of interviews with Amzon, and wish everyone luck who is looking for the next career opportunity~！