Amazon Software Development Engineer interview questions

2 back-to-back phone interviews, each interviews are for 45 minutes. After that, it took me 2 weeks to wait for the results. After I sent an email to ask for the result, the HR sent me the offer. Or I don't know how long would it take to wait.

Submitted my resume on the amazon jobs website for the entry level position as SDE or SDET. Got a response in two days inviting me for an onsite interview in Seattle. The onsite interview was in a form of a hackathon, was placed in a team of 3 and was asked to implement a piece of software together with other members of the team. Had one-on-one short interview sessions with the mentors regarding my approach to solving the given problem. Can't say specifically what the problem was about due to the NDA, in general was about data structures and object oriented design.