Online Assessment
3 tasks, I cant remember perfectly but broafly
1- Was about sorting some strings
2- Was about Ranking, you had to use hashmap and heap
3- Was about Optimization of resources
I think was pretty good, some test cases would not work on one of the tests

Onsite interview
1- Round 1
Behavioral question
System design : Amazon Fresh
I am more of a backend profile and could not see how to start.. I mentionned a warehouse components and a mysql DB.. that's it...

2- Round 2
Given a binary tree, sum the level and return the kth biggest sum
3
2 10
1 2 3 1

kSum(tree, 2) = 12
Did it quite easily but had one bug I figured out while running the code

3- Round 3
Questions
Write a event manager.
I did an observer pattern, but did not handle exception properly. Still not quite sure I did what was expected

4- Round 4
Questions
Write a factoriel function

Successfully noticed the space was small and we could just precompute all the values to get O(1). Unfortunatly, the init method was bad O(n2) and I never understood he was asking me to optimize it in O(n)

Conclusion
Amazing experience, people are really nice.
Unfortunately, I was dead tired (had a very bad night). And I read too much about people not able to do or finish the tasks.
So I was surprised by the simplicity and was always racing and waiting for the difficulty to come without realizing the task was just to backoff and get the requirements