Amazon Software Development Engineer interview questions

Two back to back interviews - both technical. In the first interview, a brief resume walkthrough and then a few questions about multithreading, trees etc. Then he asked me how to implement a queue using 2 stacks, how to do an in-order traversal of bst without recursion, compare time complexities of different operations in linked list and hash table. In the 2nd, he asked to implement algorithm to solve the word ladder problem given a dictionary. And how to implement a stack that supports minimum operation in O(1).