The process was very long, VERY.
The very first phone interview with HR person was in last December. Questions that I can recalled now are (1) tell me about your research. (2) what is the most interesting project you have done so far, and what is the worst team work experience you have so far. (3) when will you be available. etc. This phone interview was about 30 minutes, not too intense.
The second phone interview was in mid January. a tech one. He gave me a real problem he is solving (or has solved), and asked how I would approach this problem. It was an open research question and hence there is no correct answer. I gave the first answer for the simplified version of that problem and then we went from there, we gradually relaxed some constraints and improved the previous solution. The very last part of this interview was a simple coding question, about array sorting. This phone interview was about 45 minutes long.
The third phone interview was in late Feburary. In fact before they emailed me to arrange this one I thought I was out after the previous phone interview. This is a tech one also, and more about programming part. Questions are about sorting, heap, shortest path algorithm, etc. Basically I needed to explained the algorithm first, and then wrote the code on a website he provided where he can see directly what I am typing. This one was about 45 minutes as well. Questions are not too difficult, but I haven't really implement Dijkstra algorithm so it took me a while to finish it.
The fourth phone interview was in mid March, a tech one as well. He gave me a real problem he is solving now and wanted to know my opinion. This problem is about the operation optimization in amazon fulfillment center. Scheduling, picking, sorting, that kind of stuff. Again this is open research question and there is no correct answer. 45 minutes long as well.
Finally here came the onsite, it was in early April. Because I applied for a research-type job so I was required to give a seminar presentation, which is fine. (But I heard NOT all research job candidates are required to do so, which is weird, I suppose everyone should) After the hour-long presentation the interview sessions started right away. There were two tech ones first, then HR one, and then lunch break (this is a tech one as well), then two other tech ones. Each one was about 30 to 45 minutes, but you don't have to worry about the time, they will control the time. They will keep emphasizing we are almost out of time when you are trying to figure out something. That bothered me A LOT.
You can go to restroom or get something to drink between interview session, but that's basically all the rest you can get. There is no further break between sessions. So it is very exhausting. (presentation + 2 + 1 + lunch + 2, basically non-stop)
I signed NDA and hence I won't mention the details of each session. But basically all the tech sessions were about open research-type questions, probably because of the job I applied. Hence I suggest, for those who are interested in applying for Operations Research related job in amazon, google what they did, what they are doing, and what they plan to do, and think about if there is any research topics related to those. It would help a lot.
There is NO typical programming and algorithm session for me, which may not be standard I think.
The decision came in late April, I did not get the offer, which is quite disappointing, especially after such a long process. It wasn't a pleasant process because firstly it is long, and secondly because I didn't get the offer, but still I learned many things in this process, and helped me a lot in interviewing with other companies.
Oh by the way they paid for everything, flight, hotel, food, as usual.
