PlaceKode with Mathew Sachin placed at Amazon
Uthaan, the Official Journalism and Recreational Club of ABV-Indian Institute of Information Technology and Management Gwalior is back with a new season of PlaceKode to get you up to speed and prepared to get placed at the company of your dreams. With us we have Mathew Sachin who got placed at Amazon, sharing with us his journey and his interview experience.
How bewitching did it feel when you got to know that you were offered a position at a dream company like Amazon?
When Amazon came to our college, I was in my 4th year and at that time, they came to hire interns. I gave the first round which was an online test and out of nowhere was selected for the interview round. To be honest, I was not completely prepared for the interview, I just thought about giving it a try, if I got it then that’s great, otherwise, I would have tried for some other company, some other day! I felt I was a bit lucky as my interview consisted of coding questions and there was nothing from the coursework. Fortunately, I got selected and yes trust me it does feel good!
Can you give us an insight about your job profile a bit?
I am a Software Development Engineer at Amazon in the Kindle Ingestion and Management Services team. Kindle uses a proprietary internal format. So whenever a person publishes a book, it is my team’s responsibility to handle its processing, conversion and publication to the Kindle Store. The tech stack we use is mostly Java with a bit of Kotlin.
Can you describe the interview process in detail, about the rounds, the type of questions, about the interviewers and how you tackled everything?
When Amazon came on campus, I was eligible only for the internship interview. I along with 3 other people were selected from the online round for the physical interviews. Questions in that interview were pretty decent and straight forward.
You are given a number and you need to convert it into excel sheet column names like 1 to A, B to 2, 27 to AA and so on, they only asked for a pseudo code.
https://www.geeksforgeeks.org/find-excel-column-name-given-number/
You are given two linked lists which are intersecting. You need to find the intersection point of these two lists.
https://www.geeksforgeeks.org/write-a-function-to-get-the-intersection-point-of-two-linked-lists/
You are given a binary tree and you are required to print out the left view of the tree, like what are the nodes you would see from the left side.
The questions were basic but were asked in a tricky manner, like in the third question they showed a properly balanced tree so that someone might jump into conclusion that one has to print the left nodes recursively, but actually you were required to execute a level order traversal!
During the interview they were noting down our actions, what approach we were applying, what were the areas where we got stuck but at the same time they were also helping us, providing us hints wherever we got stuck. Another important tip is to always speak a bit louder in an interview, trust me it really helps a lot!
Amazon has 14 leadership principles, which are pretty much important to know while giving any interview.
On to the resume, Amazon prefers a concise one, highlighting only a few of the important projects you have done, if you have any internship experience then you can write that too, but it does not matter too much. This process took around 45 minutes to an hour including the resume part. That was the entire process for my internship, after that, I worked for two months as an intern and after that to get a full-time opportunity I had to give the conversion interview.
The conversion interview included two rounds (for some people there were 3 rounds, I was fortunate to crack that in two rounds only). The first round was again a coding round.
You are given a list of positive integers and you need to find the next largest element in the array.
https://www.geeksforgeeks.org/next-greater-element/
Given a family of ants, which includes both male and female genders and the relations between them, you are required to find whether this family is valid or not. A connection is invalid if two of the same gender were connected.
https://leetcode.com/problems/is-graph-bipartite/
As asked by Amazon here (Round 2 Question 1).
It was a disguised graph question in which the ants are considered as the nodes and the relations are the edges. Basically we need to make sure that the graph is bipartite, if it is not then the family becomes invalid.
The second and the final round included a bar raiser. Bar raisers are people who have been working in Amazon for a long time. They are almost at the top level of their organisation and very prominent people, every selection goes through them, if you got rejected in this round, then all your previous rounds become cancelled, so there was a lot at stake. He asked only one question, which was
You are given a tree and you have to find the distance of the node from the root at that point where the tree is unbalanced.
https://www.geeksforgeeks.org/find-distance-between-two-nodes-of-a-binary-tree/
After that, he asked about the internship project on which I worked for two months, its interesting parts, the challenges I faced and things like that.
What kind of approach should one apply while solving coding questions in an interview? What kind of time and space constraints were provided to you while solving those questions?
In all the interview questions you must keep in mind that the time complexity of O(n²) is not allowed, well that does not mean that you should not approach the question if you don’t know the optimised approach. The interviewer should not feel that you don’t even know the brute force solution!
You may start with a brute force solution but ultimately they expect you to come up with an optimised and more refined solution. In this process of refining your solution, they provide you with some hints as well, so you will never feel completely lost or hopeless, you just need to grab those small and broken bits and pieces they provide and apply that in your solution.
Interviews are generally stressful ventures. What things went in your mind while clearing successive rounds? Did you feel pressurised for the next round or were you relieved?
For the internship’s interview, we were told beforehand that it would be a one round process. So there was no such tension for me. The final interview for the Full Time opportunity was a Bar-Raiser Interview. Usually, the bar-raiser talks to your Project Manager and Mentor before the Interview. So, if you have done well in your internship, you are likely to get selected. This interview went pretty smooth. During the whole process, it was only once where I felt stressed. That was for the Ant Question. I was clueless for around 15 minutes thinking for the best approach. The graph algorithm didn’t cross my mind initially. I still tried to stay calm the whole time.
What was the roadmap you followed while preparing for the interview? Can you tell us about the resources you followed? Did you do any specific preparation keeping “Amazon” in mind?
I was definitely not the part of the bandwagon. Most of the students jump into Competitive Programming for cracking interviews. I only did the bare minimum of competitive programming that is enough to crack an interview. Most of my time was spent on development. As a fresher, in my first year, I went into the world of coding. I almost completed the catalogue of HackerRank. HackerRank used to be better those days. The whole of my 2nd year was dedicated to development. After gaining confidence in the development field, I again went back to coding during my 3rd year as companies were arriving for internship opportunities.
GeeksforGeeks proved to be an essential resource. It gives you an insight into different ways of solving a question. I will suggest you to first try a question yourself and then read the solution. Generally, there are no space constraints in competitive programming and hence, students tend to forget optimising the space complexity in their solution. My interviewer asked me to reduce space complexity in a few questions. Leetcode is another amazing platform to brush up your coding skills.
Amazon also gives quite a bit of importance to Behavioural Skills along with technical skills. In my case, more than 70% of my batch had solved the two coding questions in the first round. To filter out students, they asked some behavioural and work principle questions. Based on that, they selected the students for further rounds. I was given 4 options for each question. The way you answer those questions matters a lot. After joining Amazon, I got to know how much they value those 14 Principles. Obviously, there were better “Competitive Coders” than me in my batch who were not selected twice for Amazon. I firmly believe that it was due to the behavioural questions. I would say be true to yourself while answering those questions.
What kind of projects did you make before getting into the interview and what was your process for sorting the most important ones to highlight in your resume?
The interviewer rushed through my resume within one to two minutes, so it becomes very necessary to filter the ultimate projects you made, try to be very specific in your resume. My resume included only two projects one was a Screen Recording app which had 2.5K stars on Github at that time (over 5K at time of publication), made using C# and the other was an Expense Management website, which was made as a project for Internet Technologies class. Put projects which you know completely and if asked, then you should be able to hold a conversation about that project for at least 15 minutes.
How did you apply for this role? And were there any rounds online? What are the points one should keep in mind while giving an online interview?
It was an on-campus drive of Amazon where I applied. The internship selection process was before the lockdown so it was offline. The placement round was an online one. In my case, they didn’t even ask to switch on the webcam. It was an audio call with a live coding environment. They have another internal Amazon technology for this purpose. It was just a notepad kind of text editor which was visible and editable by both me and the interviewer. Generally, interviewers ask only for pseudocode, so text editors are better than an IDE as they won’t give errors.
How can we sort and filter coding questions while preparing for an interview?
Leetcode has a large set of questions asked in Amazon interviews. If you properly see those questions, read the comments and interview experiences at GeeksforGeeks, you will find that many questions repeat themselves.
As a tip, I would say, even if you know the solution, don’t come up with the best solution straightaway. Start with the basic approach and refine it further.
Any tips for juniors? How can we utilise this golden Lockdown period?
I would advise my juniors to start coding. If you are targeting Amazon, it is advisable to keep your programming fundamentals clear. But don’t dive too deep into coding that you miss out the development part. If you directly give the interview for Full time placement at Amazon, even coursework questions are asked such as Computer Networks and Operating Systems.
You should also build some projects during this period. Few of my friends had to rush and build projects during the last months for applying at companies. Some students even took other’s projects and after learning how it works, presented them as their own. So to avoid such scenarios, I would suggest my juniors have some projects ready.
Your stack doesn’t matter if you are building good things. I remember none of my seniors worked in C# but I found it most interesting and comfortable to work with. One of our seniors got placed due to Machine Learning, then everyone jumped into that. Next, someone got placed due to their App Development, then everyone started making apps. So don’t follow the herd and try to stick to a technology for a while till you learn the basics of it. You should try different stuff but choose one and focus completely on it.
Interviewed by: Shambhavi Shandilya and Somya Surendra Singh
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