Hey I recently had amazon OA for SDE-1 , it was of two question I have to solve 2 quesion and write the approach for the same in 105mins.

1- It was a amazon product related where we have 2 different versions of product and we have to arrange them in some other it was kind of medium and by some custom sorting I was able to do it .
2- It was kind of easy where a string was given and we have to find different numbers of pattern.I was able to come up with O(n) solution.

Got call next day that I have cleared the test and they will schedule a interview for me.
Any tips for preparations