Amazon Senior Software Engineer interview questions

It took quite some time (say six weeks) to get a response after I had submitted my resume, and the email came from a recruiter. The phone interview was for a position unrelated to the one for which I had submitted my resume. Setting up the phone interview took a couple of emails and a phone call, and the software engineer from the team called me precisely on time. He spent about 30 minutes asking me questions and I spent about 20 minutes asking him questions. The most technical questions were akin to: * if you had to keep a list of numeric values, how would you search it for all pairs of values which add to a fixed value? * give a back-of-the-envelope OO (class-level) design for a dictionary system A respectable amount of time was spent asking me about a technical solution I was proud of or a great technical challenge I had overcome.