Amazon Software Development Engineer interview questions

The interviews were very technically oriented thankfully. There were no behavioral questions besides the usual: "Why do you want to work with Amazon?" I was given only one problem in every interview, which surprisingly takes the greater part of the interview to solve. We communicated using CollabEdit.com. Question Number 1: //Write a method which takes an array input and returns true if the sum of any two elements is equal to the sum of the corresponding indices. // Concretely if for an array the sum of values at any two indices i and j is equal to the sum of i and j. Question Number 2: // Write a method to reverse a linked list. // State any assumptions and write any classes/structs that you will need.

Write a function to tell whether a BST is balanced