Amazon Software Development Engineer interview questions

I have been through 2 rounds for the software development engineer position. I have been asked about data structures.One is about the trees: find the distance between 2 values in a binary search tree. Node will have value, left node and right node. Implement the function int Distance(Node root, int val1, int val2) without recursion. The next question is about 2 arrays A and B.

the whole interview was easier than i thought, i was very nervous though, i didnt do good in my first interview, i didnt even had time to finish the programming question, the guy told me you are on right track but we are out of time :( my second interview was easier, it was mostly OOP design. but yesterday i got an email that they want 3rd interview