Amazon Software Developer interview questions

Applied through my school's recruiting website, received an email from a recruiter within couple of days. The recruiter set up first technical phone screening where they asked typical questions like data structures, design, BST. After one week, the recruited set up a second phone interview which was more or less similar to the first one. Algorithms questions, coding, debugging. Recruiter emailed back to set up time for onsite interview. I'm still looking into my calendar.

I submitted the resume online. HR contacted me in the next day and scheduled a phone interview. The questions including basic OO concept, data structure ( hash, BST). some classic algorithms. For eg: 1. abstract class and interface 2. virtual deconstructor 3. an array of integer with all the numbers occur even times except one number occur odd times, find it. I was asked to write codes to reverse a string.