Amazon Software Engineer interview questions

How would you implement a priority queue. What is the O analysis of your implementation. How would you store a tree structure. How would you implement a tinyURL service.

given a tree write a function isSymmetrical that would find out if the tree is symmetric or not. ----- Class Node { Node leftChild Node rightChild; int value; } //Write this method: boolean isSymmetrical(Node treeRoot) { Examples: This is symmetrical 7 / \ 5 5 / \ 9 9 / \ / \ 2 8 8 2 This is not symmetrical (value difference): 7 / \ 5 6 / \ 9 9 / \ / \ 2 8 8 2 This is not symmetrical (structural difference) 7 / \ 5 5 / \ 9 9 / \ / 2 8 8