Online Assessment: There was an online coding assessment in which you had two solve 2 coding questions in 70 min followed by behavioral pattern questions separately. Both coding questions were medium level and I was able to solve almost both of them. After one week of this round, I got a selection mail from their recruitment team for the next rounds. All the interviews were conducted on the Amazon Chime platform.
Technical Round 1: The interviewer was SDE – 2 at Amazon. He started with a quick introduction. After that, we moved to coding questions. He pasted a question on the text editor and also explained that to me. I was asked to explain the best approach, write code for it and tell about space and time complexity.
- https://www.geeksforgeeks.org/flip-binary-tree/amp/
- https://leetcode.com/problems/find-the-celebrity/
I was able to solve both questions in the given time.
Technical Round 2: The interviewer was an SDE-2 at Amazon. He first asked for an introduction followed by questions on leadership principles. He then moved to coding questions:
- Given an array of size N, find the number of Next Greater Elements for all the array elements
Input: {3,4,2,7,5,8,10,6}
Output: {4,3,3,2,2,1,0,0}
Explanation: For 3 NGE is 4, For 4 NGE is 7, for 7 NGE is 8 and for 8 NGE is 10.
Hence the number of NGE to the right of 3 is 4
I solved this using Stacks in O(N) time and space complexity -
https://www.geeksforgeeks.org/split-given-array-in-minimum-number-of-subarrays-such-that-rearranging-the-order-of-subarrays-sorts-the-array/amp/
Solved this by comparing with the sorted version of the array
Bar-Raiser Round: The interviewer was SDE-2. He asked for an introduction and then jumped into the coding questions:
- Given an array of size N, The array elements which are identical and adjacent are removed from the array. Find the number of elements left after removing the identical elements
Input: {2,3,3,1,5,5,1,6,7}
Output: 3
Explanation: Initially 3,5 can be removed. After removing the array will be {2,1,1,6,7}
Now, 1 can be removed. So, the array will be {2,6,7}
Nothing can be removed from this array. Hence the output is 3.
Solved this using Stacks in O(N) time and space complexity - Find the level of the tree which has the maximum number of nodes. Print the level number as well as the sum of nodes of that level
Solved using Queue in O(N) time and space complexity.
I solved both questions and then he proceeded to behavioral questions.
Verdict: Selected.