I applied through college or university. The process took 1 day. I interviewed at Amazon in Dec 2014
Interview
There was a test on Hackerrank.com which consisted of MCQs and coding questions. There were 3 rounds of technical interview. In each round of the interview I was asked a question based on algorithms & datastructures. Initially in each round you are expected to come up with an algorithm for a problem they provide to you. After you have derived to decent algorithm you need to write an "amazon" quality code on a piece paper.
Interview questions [1]
Question 1
In 2nd round of interview problem posed to me was a bit difficult with non-intuitive solution. It took a while even with interviewer's help to reach to a good algorithm.
I applied online. The process took 2 months. I interviewed at Amazon in Sep 2013
Interview
Four round back to back interviews after lunch. All 45 minutes. All data structure/ algorithm based questions. And bunch of behavior questions.
A senior manager asked me to write a Stack, and get a min value of that Stack. Which is a little surprised. And then some kinds of pressure testing :/
Not so hard. If you prepared well, you should be OK.
I applied online. The process took 4 months. I interviewed at Amazon in Jan 2015
Interview
I was contacted by amazon about half a year after I applied. I did the online assessment, a phone/video screening, and an all day in person interview. The interview on site was the hardest. 4 of the 5 interviews were technical and one was behavioral. I signed an NDA so I won't give specific questions, but I will tell you what I did to prepare.
I read through the entire Cracking the Coding Interview book (I didn't have time to do all the problems but I made sure I understood the answers). I took the Algorithms class on coursera (they offer two sequential classes). That was probably one of the most helpful things. Those classes go over exactly what you need to know - data structures, algorithms, etc. They didn't ask me directly about the data structures (i.e. What is a hash table?) but I did need to know exactly what my options were and the properties of each data structure. For each problem, I had to choose which structures were appropriate and explain why. So I had to know them inside and out. I would strongly recommend going through all the common data structures and refreshing how they work, what they are best for, and the complexity of each operation.
I would also suggest learning about Amazon specifically - what their teams do, what languages and database systems they use. I did, so I was able to ask my interviewers good questions.
During the interview, I was extremely nervous but I made sure to talk through everything I was doing and thinking about even if I didn't have a solution in mind right away. I recommend trying to minimize silent moments.
Interview questions [1]
Question 1
The most difficult question was a design question. It was open ended and there was no one right answer. I would suggest practicing design questions such as "design a parking lot" or "design a card game" and figuring out all the details and possible problems.