Amazon Software Developer Intern interview questions

Applied mid-Jan. Got an email invitation for a phone interview one week from applying. Standard two back-to-back interviews, 45 minutes each. Both interviews started out with basic data structures question and moved on to coding for the last 20 minutes. Questions ranged from Queues vs Stacks, Time complexities to perform all sorts of operations on Graph structures to what data structure to use given a particular situation. Coding problems were easy (Merge two linked lists) but I screwed up the syntax a bit.

two back-to-back 45min interview. They asked me four questions in total. Not so difficult but I didn't answer it well, I mean, using the best way.