Amazon Software Development Engineer interview questions

It was in-campus recruitment. Initially there was an online round consisting of 20 multiple choice questions and 2 programming questions. The MCQs were mix of aptitude and technical. 17 students were shortlisted, out of which top 5 scorers advanced to interview round. The others had further technical round and one of the questions was on doubly linked list. It was an elimination round and those who passed, joined the top 5 for interview. The interview was mostly technical (no HR interview) and there was one interviewer in each interview round. Questions were asked related to project work we have done in the past(as mentioned in resume). Besides, we had to write code (on A4 sheets) regarding trees and lots of question on time-complexity. No. of interviews varied from student to student. I had two.

The interview was over the phone and used a collaborative document to allow me and the interviewer to see what each other was typing. This document was also used to share code. The interview was almost entirely technical, feeding me one problem after another. First, they asked me about Fibonacci number sequences to see if I knew anything about them and whether I could construct a method to calculate any number in the sequence by inputting what number it was in the sequence (e.g. 1 for the 3rd number, 3 for the 5th number). This was solved using a recursive solution due to the Fibonacci sequence being a recursive sequence, but the interviewer also suggested that there were non-recursive methods. He asked me to generate test cases for the method I just created. Next, the interviewer wanted me to create a structure that represents a binary search tree and write a boolean function that verified to see whether a parameter was a binary search tree.