Amazon Software Development Engineer interview questions

two 45 min phone screens. mostly technical. if you pass, get invited for on-site interview. on-site interview consisted of five ~1 hour interviews, one being lunch w/ manager(s). They all come up with their own questions and have you write solutions on a white board. No brain teasers really but some of the questions were quite difficult. The interviewers were extremely smart and overall friendly.

First there was a email for you to choose you available interview schedule. I chose a date about three weeks after receiving that email to get fully prepared. There are two phone interview with 45 mins each and a 15 mins break in the middle. First interviewer asked me two questions: 1. Find the only one duplicated number in an array. The idea is easy: using hashtable. 2. Print the Fibonacci sequence until current number is bigger than a MAX value. My idea is to use a while loop until meet the condition. Also there were some concepts about Java generics and Java multi-threading. The second interviewer only asked me one big question: find the longest repeated substring in a string.(e.g., "banana" -> "ana"; "I am what I am" -> "I am"). This is little tricky one and I didn't have ideas in the beginning. But I figured it out gradually with a O(n2) algorithm after he push me to speak what am I thinking. During the coding, he found some bugs and I fixed one by one. At last the codes ran perfectly. I got the offer exactly two weeks later.