There is four round of interviews.
Round 1 (Online Assessment Test): The online test consists of 2 coding questions to be completed in 70 minutes. The questions are of medium difficulty level and I was able to solve both of them in under 40 minutes.
One of them was a variant of this question https://www.geeksforgeeks.org/find-maximum-minimum-sum-subarray-size-k/amp/
Round 2 (Technical Interview): My interviewer asked me to introduce myself and then jumped into coding questions :
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Question 1: Check if the given BST is a sum tree
I gave him an optimized solution and discussed its time complexity.
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Question 2: You will start at a point (X, Y) on a grid of dimensions (M, N). Return the no. of ways in which you can cross the border of the grid in exactly k steps.
I initially gave a brute force solution. Later I was able to optimize my code. My interviewer was very friendly he helped me here and there if they were any errors in my code. Overall I was able to solve both the questions in under 50 minutes. Later we had a casual discussion on projects and work culture at Amazon for a few minutes.
Round 3 (Technical Interview): He gave an introduction about himself and asked me to do the same. Later he asked me a coding question:
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Question 1: Find the maximum sum subtree which is also a BST in a binary tree.
I solved the question and explained my approach and the time complexity of my solution to him. He then showed me multiple code snippets and asked me to calculate time complexities for each of them. He asked to calculate the time complexity of the Sieve of the Eratosthenes algorithm.
Round 4 (Final Round/Bar Raiser): We had a discussion on my previous projects for around 30 minutes. He then asked me a few behavioral questions:
- Tell me about a time when you have exceeded expectations.
- Tell me about a time when you have delivered late? If yes what was the reason for the delay?
- Why do you want to leave your current company?
- Why Amazon?
He then asked me to write production-quality code for the following question- https://www.geeksforgeeks.org/sort-the-strings-according-to-its-frequency/amp/
Final Result: Selected.