Amazon Interview Experience for SDE 1 | OFF-Campus – 2019
A recruiter contacted me through INSTAHYRE (Job searching platform), I have my profile on a lot of platforms, but Instahyre seems to be the most genuine one. So I got a mail from Amazon HR, he called me for an onsite interview at Amazon Bangalore.
Around 60-70 candidates were there on the interview day. There were 4 rounds, each one was elimination round. After interview rounds there was 1 more round on skype call.
Round 1(Written Round): Generally amazon conducts an online assessment, but in my case, they conducted a written round at the venue with the same format as that of online assessment- 2 Coding Questions in 60 minutes. MCQs were not there.
- Find all triplets with zero sum
- Replace each node in binary tree with the sum of its inorder predecessor and successor
Questions were easy, but their main focus was on Time and Space Complexities. After this round, some 50 students were left.
Round 2 ( Face to face interview): This round was focused only on my DS and ALGO skills. The interviewer was very friendly. He gave me 2 questions and asked me to first discuss the approach, and then implement production-ready code for the problems. The main focus in this round was:
- To optimize the solution to best possible complexities.
- Write production-ready code, your implementation will be tested, you have to write a code that would run without any compilation error or runtime error if tested on a system, even a small mistake can lead to your rejection.
- This was recursion and memorization based. This took a lot of time, I was trying to solve this, but since I saw this question for the first time, I was a bit afraid, interviewer was friendly, he helped me with some hints and finally we reached to a solution.: https://www.hackerrank.com/challenges/grid-walking/problem
- This was hashmap and tree-based problem https://www.geeksforgeeks.org/construct-a-binary-tree-from-parent-array-representation/:
This round went well, and I was qualified for the next round.
Round 3( Face to face interview): This round was also focused on DS, ALGO. Interviewer asked basic details about my projects and then he asked 2 questions.
- It was a string problem, the question was of medium difficulty, I was able to solve this in less time. https://www.geeksforgeeks.org/find-the-smallest-window-in-a-string-containing-all-characters-of-another-string/
- This question a standard DP problem – Buying and selling stocks with max profit if only k transactions are allowed. He started with basic version and then moved to the standard version. https://www.geeksforgeeks.org/maximum-profit-by-buying-and-selling-a-share-at-most-k-times/ .
I cleared this round.
Round 4( Face to face interview): This round was focused more on CORE knowledge (OS and DBMS only, no Networking questions were asked.). He discussed my projects in great detail, be ready to answer each and every minute detail about the projects mentioned in your resume. After this, since I’m a C++ guy, he asked me some questions about C++ like:
- How C++ has evolved from C++ to C++17?
- What is diamond problem?
- How virtual keyword works?
- Questions about multi threading in C++.
- How C++ compiler works in detail.
Then he moved to core subject questions i.e., OS and DBMS, he gave me some scenarios and asked me how OS would behave, how it will handle all this, how semaphores will help, what is virtual memory, how does page replacement algorithms work. In DBMS he asked me about Indexing in detail, how actually indexing works in DBMS.
I cleared this round and then I was told that I will have one more Round of interview on skype and that would be a technical one.
Round 4(Online call): Interview started with his introduction, and then my introduction. Then he asked questions about my academic project. Then he asked some behavioural question like Why Amazon?, What motivates you?, What have you learnt on your own?. After these questions, he asked me one easy coding problem. After discussing the approach he asked me to write production-ready code for this.
Next day I got a call from HR congratulating me for bagging SDE 1 offer at Amazon.
- One month before your interview, start practising coding problems by implementing them on paper as during the interview they would expect a production-ready code which means that if they write that same code in their system it would run without any compilation error.
- Improve your communication, it doesn’t mean improving English, just make sure that during the interview, the interviewer gets to know about your thought process, that would help him in making the correct decision even if you’re unable to solve the problem.
- Go through your resume, you should be able to answer every question about anything mentioned on your resume.
- Write you knowledge level with every skill that you are mentioning in your resume like if you are good enough in C++, mention it s PROFICIENT skill.
- Don’t panic if you see a new question. Try to solve that as if you are sitting with a friend, it’s a part of the interview.
- Always think as an interviewer during the interview, like what would you expect from someone if you were interviewing a guy and he is in the same circumstance as you are.
- It’s your responsibility to get your strength noticed by interviewer.
All the best!! Happy coding!!