Getting help from the Leetcode community for a long time. I just wanted to give something back as well. :)
I gave an amazon interview last week and wanted to share my experience. I had given an online test prior to the onsites some time back but i do not remember the questions that well. Two weeks later, I was asked to come for onsites.
Pointers before discussing about onsites questions:

1. Every round was a coding round alongside LP round.
2. The rounds also consisted of a few questions asked in relation to core subjects like Operating Systems, DBMS, Networks etc.
3. Each round had atleast two coding questions asked.
4. Each round went on for atleast an hour in my case

Round 1: I was asked two questions. Both being from leetcode and of medium difficulty. Topics begin Trees and Arrays.

1. Given a binary tree and a sum. Find if there exists a path from root to leaf with sum of node values to be equal to the target value given.- https://leetcode.com/problems/path-sum/
   I was able to come up with an O(n) solution and was able to code up pretty fast.
2. Trapping rainwater problem-https://leetcode.com/problems/trapping-rain-water/
   This is a pretty well known problem and I did remember it doing a long time back. I had a discussion with the interviewer and was able to come up with an O(n) time and space solution. We went further discussing on STLs in C++ and couple of other topics.
3. Apart from this there was a resume discussion and couple of LP questions as well.

Round 2: Questions again were from leetcode. The topics asked were from stacks and heaps.

1. Given a stream of integers, find the median of numbers at any point.
   I had never seen this question before hand, but first come up with a brute-force approach, but with a couple of hints from the interviewer I came up with a heap solution there. Later saw that this question is pretty well known leetcode-hard question.
   https://leetcode.com/problems/find-median-from-data-stream/
2. Perform Push, Pop and Get_Min in O(1) complexity.
   This question was easy and I had a good discussion with the interviewer about different approaches.
3. Here I was asked questions from OOPS and Networking. I was able to answer question from OOPS but unable to answer the questions from networking.

Round 3: I was asked three questions in this round. I was asked mostly DP and one Heap question in this round.

1. The question was given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.
   I had never seen this question before and DP being a weak spot for me, I was unable to come up with a DP solution of this problem. I gave a recursive approach but was unable to further optimise it. Later found out that this question was available on leetcode as well.
   https://leetcode.com/problems/interleaving-string/
2. The next question was again from DP, and I had seen the question before. The question was Decode Ways-https://leetcode.com/problems/decode-ways/
   I was able to come up with both a tabularised and a recursive approach for this problem. I had a good amount of discussion with the interviewer on this question.
3. Later on, I was asked the question on K-frequent words from a stream of words incoming. I was able to come up with a brute force solution and then the interviewer asked me to code it up. Post that we had a discussion on everything in relation to designing of the hashmap and priority queues which was in relation to the question.
4. The interviewer also asked a couple of DBMS questions like ACID properties and some SQL queries.

Round 4: This was the last round. I was asked two questions here. I bombed this interview pretty badly, even though I was able to code it up but I took a lot of time even though the questions weren't that tough.

1. I was asked a couple of LP questions and things from my resume. Even though I was able to answer LP questions comfortably, I had not revised my resume projects that thoroughly and the interviewer went in depth analysis of my projects where I was unable to answer a couple of questions mainly because I hadn't revised.
2. It was a graph problem to be done using minheaps. I coded up that solution pretty fast. We had a discussion on minheaps and I was asked to write a code for minheap extraction which was the part where I made a mistake. I got confused in one point and I took a lot of time thinking and kept getting confused further. After sometime, the interviewer started getting slighly frustrated gave me a hint from which I was able to code up the question. I got so nervous and then gave the incorrect complexity analysis of it.
3. The second question was Word ladder - https://leetcode.com/problems/word-ladder/
   I gave the brute force analysis and since I was nervous from the prior mistake I ended up again giving incorrect time complexity analysis. The interviewer helped me a bit further and I was able to come up with a optimised solution but since I had already taken a lot of time, I was unable to code that up.

Mistakes that I actually learnt from after giving the inteviews:

• Revise everything on your resume that you think can be asked from you. Getting rejected just because you weren't able to answer something you had done a long time back sucks badly.
• Even if you have made mistakes in one round or asked too many hints don't let that boggle you down. Consider every question a new opportunity in that interview irrespective of how the previous one went.
• Get your time complexity analysis right. I realised that this concept still is an extremly weak portion of mine.
• Interviews are luck based, but the only thing you can do is give your best shot so that you never have regret of not trying.
• Rejections happen all the time and I'm pretty sure everyone here must have faced that atleast once. Just take it as a learning experience and move forward. Maybe that company wasn't for you right now, but that doesn't mean it will never be in the future.

I hope this experience is helpful to anyone who is trying in Amazon and I hope you do get in. All the best :)