Amazon Software Development Engineer interview questions

I was interviewed in Seattle for the position of SDE. First round was telephonic. The call lasted for 90 minutes and I was asked to code on a notepad shared by both of us. The questions were related to OOPS. Second round was face to face in Seattle which included 5 rounds from 11AM to 4PM. Each round was around 45 mins long and all were technical round.

4 round 1:1, each one 45 minutes Each round ask you some background question and one programming question 1 make file, choose a data structure to implement, (my answer is graph, do topology sort) 2 file system, object oriented design, design two classes 3 array of number, sum up to n, print out all pairs 4 binary tree, given two node, find first common ancestor, without pointer to parent node