It started from a campus recruiting process for finding summer SE interns. The interview consisted of 2 sections, in which I interacted with an Amazon.com's recruiter in each section alone. First section: Tree Traversal I was asked about the best implementation for a binary tree (i.e. pre-order, in-order, post-order). I was required to communicate reasons why I chose to use a particular one. Second section: Iterative and Recursive Arithmetic Implementation I was asked to find sums of next N numbers in an array iteratively and recursively. I came out with the iterative approach within a short period of time, and the recruiter asked for the recursive approach. Note: The recruiters asked questions unrelated to programming too. For instance, they asked the reasons why I chose Amazon.com as a candidate company for my internship. They wanted to see my thoughts