Amazon Software Engineer Interview Experience — Virtual Onsite with BQ, an OO Ticket System, and a Recommendation Engine

This was a virtual onsite. The interviewer told me right away that he'd be taking a lot of notes, so I shouldn't read too much into it.

BQ section:

The first question was on "Ownership" — he asked if I'd ever run into something that wasn't technically part of my responsibilities but I went ahead and took care of it anyway.

The second was "Deliver Results" — he asked for an example of delivering something under a tight deadline with limited resources.

Coding/Design section:

This round was a design question with a bit of an OO flavor — I had to write an EventTicketSystem that could sell different kinds of tickets (think concerts, movies, sports events), with the requirement that it be extensible, so adding a new ticket type later wouldn't require a big rewrite of the logic.

I used a simple factory pattern, abstracting out the ticket type, with the core logic living in a ticket seller class.

Partway through he pushed on me: what if each ticket type ends up needing a different price calculation rule down the line? I talked through decoupling that with a strategy pattern, and I think that point earned me some bonus points.

There was a fair amount of code to write, and I basically finished right up against the time limit. The interviewer said, "That's pretty aligned with what I expected," and laughed a bit.

The system design part was designing an Amazon product recommendation system, which I personally found fairly hard.

Overall the vibe was pretty good, and the feedback was good too — but I feel like Amazon's bar has really gone up recently, and BQ often runs into a bar raiser. My advice: don't take BQ prep lightly, have more than one version of your stories ready.