Amazon Chennai conducted drive for SDE 1 and SDE 2 recently on 28th September in Delhi
Initially there was a written round where we were asked to write algorithms for certain problems. The problems were of medium level. There were total 3 problems as:
Problem 3: Wild card pattern matching
- Given a binary tree, find the difference between sum of all the elements at odd and even level of the tree. The level of tree were considered diagonally. (expected space complexity O(1), time complexity O(n).
- It was a standard DP question, we have to find the maximum possible sum to reach the last row of matrix starting from top left corner and only possible moves were going down and diagonally right.
Then he asked me some behavioral questions.
- Maximum sum path in a binary tree
- He started this question by framing a story just like we find for every question on codechef but it turn out be one of the DP problem (word-break problem). I told him my approach using Trie and it worked on some test cases too but couldn’t provide the efficient solution using DP. I had never seen this question before but later got to know it is one of the common question to be asked.
Round 3 (F2F Hiring Manager):
He was one of the senior manager of the team for which this hiring drive was conducted. Firstly, he asked me to introduce myself and then he asked many behavioral questions based on amazon principles.
Only 3 rounds were conducted on that day and HR told me that next round will be conducted over video conferencing.
Round 4 (Bar Raiser):
This round was conducted after two weeks and the interviewer was a senior manager having more than 10 years of experience at amazon itself. He started with my introduction and then asked behavioral questions based on amazon principles like :
- Tell me a situation when you worked on something beside your team
- If there is a product release tomorrow and you came to know that there are many bugs in product which would take at least a two weeks, what would you do in this situation.
- Best project you have worked on.
He also asked some questions from Operating Systems on scheduling algorithms, race condition, how mutex and semaphores work and there practical implementation, how data is saved on disk.
He wanted to ask questions on design patterns also but i replied that i am not much knowledge of that.
At last, i was asked to solve on algorithmic problem which was given a text file of words and spaces with no punctuation and we need to compress this file in order to reduce the actual size of the file.
After two weeks i got the call from HR that i have been shortlisted for this position.
Note: At every stage you are expected to write clean, simple and efficient code with minimal possible time complexity on paper or whiteboard. Even if you are not sure about your solution, tell the interviewer about your thought process and approach as sometimes they are not just looking for the exact solution rather they judge you on your thinking ability and how you see the problem in itself.
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