Amazon Interview Experience

First round was an online test which had around 30 MCQs on DS and C++ and 2 coding questions. Given time to complete it was 90 mins. So efficient way would be to use 30 mins for each coding question and remaining 30 mins for MCQs. Both the coding questions were medium level, one on strings and other on trees. Solved both of them.

Got shortlisted and they mailed me my interview dates along with topics that I had to prepare and I had 15 days of time before my interview.

I started working on writing code on white paper, Data Structures and problem solving. I read about System design and design patterns along with main concepts of other core subjects like DBMS and OS. One must be familiar with the Leadership principles of Amazon as well.

I had 4 rounds of interview. They informed that I would be meeting 3-4 Amazonians.

Every round had problem solving questions related to DSA. They give you question and some time to think for the same. When you almost approach the solution, they say you to write and you have to write the entire code on white paper. So you better be proficient with one of the OOPs language. And they might say you to improve efficiency of it, given it has a better solution than whatever you have written on paper.

There might be 2-3 problem solving questions in each round. They do it to check your hold on programming language, Data structures and Algorithms.

Last round was with manager and even this was a technical round. He gave me 2 questions and told me to write the code. He asked me questions on OS and about my projects. They check the leadership principles here. They ask some behavioral questions as well. Everything went well. They told me that I would get to know about results through mail in few days.

I did not answer every questions in all the round. But I answered 70-80% and there were instances where interviewers helped me to continue solving, if I was struck somewhere in the middle. You need to tell them your approach and say them how you are going to solve it along with writing code, they will give you some hints if you get struck somewhere. So if you don't get the exact solution after some time, at least discuss with them what's going on in your mind.

Regarding coding questions and problem solving, I don't remember exact questions but it almost covered data structures like stack, linked lists, trees, heap, graph and Traversal of graphs and trees. Algorithm techniques like greedy and DP. I had solved one question in one of the round in Brute force technique. So if you are not getting idea, try to do it in brute force and later they will help or give you a hint to proceed with increasing the efficiency of it. Talk to them properly, say what is running in your mind, be calm and trust yourself.

At the end of every round, they give you a chance to ask them questions. Utilize it well and ask anything you wanna know.

I went to interview hoping to get an experience, that would help me prepare well for next time. I knew I wasn't completely prepared, I had so much more to learn. But I was confident about those things that I had in my resume. I wanted to clear all the rounds but I was not so much sure about that. As my first round of interview started, I did good. I knew I would qualify for next one. That went a little well. As I went to successive rounds my confidence increased and I thought I would be happier that at least I attended all the rounds. At the end of the day same happened. I was happy that I could make it until the last round. I did well, but I knew I could have done still better. I wasn't expecting the offer, but I came to know about what else I am not good at and what other things I should start preparing, where and all I need to improve. Got the results within a week. That day was a memorable one.

I started preparing in my 6th semester. I wish I had started it earlier. I am not a pro at coding, I am an average coder. There is still much more to learn and I am still learning.

Sources that helped me are

1. Data structure and algorithms made easy by Narasimha Karumanchi.
2. Cracking the coding algorithm by Gayle McDowell.
3. Operating system by Avi Silberschatz.
4. All the other concepts like DBMS and must do coding questions in GeeksforGeeks.
5. I started coding in Hackerrank, then moved to Codeforces. Leetcode also has best set of questions.
6. To learn Java, YouTube videos of Telusko channel.
7. System Design and Object Oriented Programming YouTube videos by Gaurav Sen.

Also, regarding CP, it is not about your rating, but how much you learnt in the process is what matters at beginning. When I started CP in codeforces I could solve only question A in Div 2 contests. After so much of practice and efforts I was able to do both A and B in Div 2. I practiced everyday. I struggled in initial phases of coding in codeforces, but I worked on it, even now whenever I get free time I try to solve questions in codeforce contests. Solving A,B,C questions in the contest were the happiest days after giving it so much of time and practice. So just keep on learning, practice everyday and be consistent.

Last but not least Believe in Yourself. Main thing to crack any kind of exam or interview.