Amazon Software Engineer interview questions

Applied on career fair. Recruiters at the career fair asked 2 technical questions. First is how to sort 5 sorted integer array into one big array. The second one is how to give change with minimal number of coins. Get the on-site interview in Seattle after Career fair, no phone interview. There're 4 interviews that day. First one, 2 questions. The first question is pretty complicated, but the skills the interviewer was seeking are searching and constructing binary tree. The second question is how to implement a stack using 2 queues. Second one, don't remember... Third one, given 2 character arrays, check if all the characters in one array can be found in the other array. Last one, 2 questions. 1. given 2 sorted integer arrays, find the median number of two arrays together. 2. how to print a binary tree level by level in reverse order.(level 1, from left to right' level2, from right to left...).