Amazon Software Developer Interview Questions and Answers

Round: Test
Experience: 1 Written Test - (20 MCQ + 2 Coding Questions) on HackerRankAmazon visited our Campus on 28th July. In the morning the recruitment process started with the Written Test. It was taken on Hacker Rank which comprised of 20 MCQ Questions followed by 2 Programming Questions. MCQ Questions usually contain questions on C, DBMS, OS, and 4-5 Logical Questions. One should be aware that the Hacker Rank platform keeps record of how much time you have spent on each Question and after spending so much time did you attempt it or not. The 2 Coding Problems were quite easy. Only speed and accuracy was required to crack this round.Written Round Coding Question -1) A Linked List was given and we had to swap the ith node with (n-i+1)th node.2)(given some intervals), merge the common Intervals.I coded both the problems and passed all the test cases of the first question and half of the test cases of the 2nd Question. By the evening the results of the written round were declared and the Interview Process started. I rushed to the Design Centre and while I was arranging my grade sheets and my resume , something totally unexpected happened. One of the Amazon Employees who was also an Alumni of MNIT Jaipur walked up to me and told me that I have done very well in the Written Test and I was ranked 2nd based on the Written Test. He wished me ‘Best of Luck’ and told me to calm down and give my best. Talking to him really motivated me a lot. At the same time I was shocked that he still remembered my name even after an year, as we had talked only for a couple of minutes during my Internship Process in Amazon in which I was among the last 3 Students who went to the final round but was not selected. Apart from the students shortlisted from the written test, Amazon also shortlists around 5-6 more candidates based on their CGPA and some other factors. But it should be noted that at any time during the Recruitment Process, Cumulative scores can be considered.
Tips: CGPA above 8 should definitely be maintained.
Total Questions: 22

Round: Technical Interview
Experience: The Interview Process started with around 25 candidates. I was among the first few with whom the Interview had started which went on smoothly



Questions of Interview Round II –



1) A String was given with a lot of words in it and I had to reverse all the words
2) A String was given and I have to swap word by word from the  beginning to the end.
3) In question 2 when there are ‘n’ in the String whose position shouldn’t get affected during the swapping process
4) Continuation was when more than 1 ‘n’ occur together.



I was asked to code the above, and told them about the time and space complexities. Then he went through my resume and based on my projects he appreciated my interest in OS. and asked me a Question –


You have a large game and a small memory, so how will you play the game.
I told him the concept of Virtual Memory and how it makes it possible to run such a game. Then he asked me whether there is any limit or constraint on the size of the virtual memory. I explained to him if the amount of memory required at any particular moment of time to run the game, itself exceeds the available size in the RAM for the user, then we won’t be able to play. Then he asked “Suppose you have a 4 GB Ram then how much memory will be available to the user and what will happen to the other memory”. I explained that kernel occupies some memory and apart from that page tables and all are also stored in the memory. Then there were some discussions regarding my projects.
Tips: These is some Important stuff which one should not miss while preparing for the interviews :


Languages one should be knowing for Placements:
1) C : For most of the companies
2) C ++ - For Faster coding using Standard Template Libraries and for OOPS Concept3) Java – For some specific companies which are focused on Java


Operating System:
1) Galvin Text Book
2) Video Lectures by Prof. Kamakoti – IIT Bombay (Not available on NPTEL. You can get it from current student of IIT Bombay or take it from me. I have Video Lectures of 2013 Pass out Batch)
3) Good grasp on OS implementation on Linux and Pint OS.
4) Detail Knowledge of How Threading is implemented in JAVA


Computer Networks:
1) Video Lectures by Prof. Sujoy Ghosh – IIT Kharagpur (Available on NPTEL)
2) Good grasp on Linux Networking (Servers and Networking Commands)


DBMS :
1) SQL Queries.
2) Database Implementation in MY SQL (Using B trees)
3) Indexing and Hashing in DBMS
4) Drawbacks of SQL Database
5) No SQL Database – Graph and Document Type Database and how they solve the problems
6) Every minute detail of the Database you have created in your DBMS Project.


Data Structures and Algorithms:
1) Video Lectures on Data Structures by Prof Naveen Garg – IIT Delhi (Available on NPTEL)
2) Video Lectures on Data Structure and Algorithm by Prof. Charles Leiserson and Prof. Erik Demaine - MIT.
3) TextBook – “Data Structures and Algorithms made Easy” by Karumanchi
4) TextBook – “Cracking the Coding Interview” by Gayle Laakmann Founder and CEO, CareerCup.com
5) GeeksforGeeks6) Company Specific Preparation by Practicing Previous Interview Papers


Programming Practices:
1) Codechef or Any other Coding Website: Experience helps to increase your Programming Speed, definitely useful in qualifying Coding Round
2) Standard Template Library in C++ for faster Coding - Hacker Rank Tutorial


Other Stuff to Study:
1) Brain Teasers
2) Design Problems (asked by Companies like Adobe. Detailed Example in Karumanchi Textbook)
3) Logical And Aptitude Preparation – Arun Sharma TextBook
4) HR Interview preparation from Indiabix.com

Round: Other Interview
Experience: Around 17 students were shortlisted. The resumes of students and their academic projects were given importance while shortlisting for this round. It started at around 10PM.



Questions of Interview Round III –



1) There is a big file containing numbers and we have to sort all of them.



I mentioned the approach mentioned in GeeksforGeeks that for example the available RAM for this purpose is 100 MB. So we can break the File in chunks of 100 Mb and bring the chunks in Memory and first sort them individually. Then we can prepare a heap containing first elements from all chunks. And keep extracting min from heap and replace it by next smallest element of the chunk it belongs. Then he asked if the number of chunks being formed here are very large, that is the heap I am preparing won’t fit in 100MB, then what to do. I suggested some further modifications and finally he was satisfied with the solution.



2) How to implement word suggestions like that in Eclipse.



I explained that it can be done using Tree Data Structure or using some sort of multilevel hashing in combination with storing words in sorted form. He asked me time complexities and told me to think of further improvements. He wasn’t completely satisfied and moved onto the next question.



3) Given 2 integers a and b, the sequence which will be formed is a, b, a+b, a+2b….



i.e Current element = sum of the previous 2 elements.



So now given a number k, how to figure out if it lies in the sequence or not.



This Question is not as easy as it looks. Here a and b can be negative or positive so the Generated Sequence can contain all positive or all negative or alternate occurrence of positive and negative element in sequence. So till which point should we generate the sequence and decide that k can or cannot lie in the sequence. I wrote a code but he mentioned few test cases in which my code was failing. After a few modifications I was able to write a satisfactory code solving all the test cases.

Round: Other Interview
Experience: I answered both the questions and also mentioned  solution to kth largest if Deletion operation is also there and if it is not. Then he told me to write the code for Heapify Function. Again there were some discussion regarding my Projects.

Round: Other Interview
Experience: Questions of Interview Round V -
This round started with a detailed discussion about my Summer Internship Project in Wooqer. After that I was asked to introduce myself. Then he asked me -

1) Given an Infix expression, how to evaluate its answer.

I was asked to write the code for it covering all the cases and I was given half an hour to do it. I wrote it in about 15-20 minutes. Interview of 4th Round got over by about 9 PM, and the results were declared by 11PM.
Tips: Amazon mostly focuses on – Tries, Big Data, Hashing, Strings. Apart from my general preparation for the Interview, I had gone through around 60 Amazon Interview Papers available on GeeksforGeeks, so I was totally aware of the kind of Questions I would be facing in the Interview, and prepared myself accordingly. In this year’s Amazon Interviews mostly the questions asked were not directly from GeeksforGeeks. And few questions which were picked directly from GeeksforGeeks, the solution they were expecting for it was better than that mentioned in GeekforGeeks. But to guess such a solution, one should surely be aware of all the existing solutions in GeeksforGeeks.

General Tips: Self Projects have a very high weight age in one's selection because this is one of the many things that distinguishes you from other candidates sitting in the Interview. It also shows your capabilities and your field of Interest. Also, Summer Internship surely matters a lot in Companies like Amazon. There was a very detail discussion of my Internship at Wooqer during the Interview Process at Amazon so be prepared.
College Name: NIT JAIPUR

Topics to prepare for Amazon Software Developer interview:

• Excel
• Data Entry
• Project Management
• Ms World
• Programming
• Google software developer
• Microsoft software developer

Interview preparation tips for other job seekers - Here are some tips and advice for seekers looking to land a role at amazon software developer....
1. Understand Amazon's culture:?
2. Review job description ?
3.update your resume.? B
INTERVIEW PREPARATION
1.Research the team and role ?
2. Prepare to talk about your experience?
3.How would you solve?
4.What are your strengths and weakness?

Topics to prepare for Amazon Software Developer interview:

• Data Structures
• Algorithms
• System Design
• Object Oriented Design
• Amazon Leadership Principles

Interview preparation tips for other job seekers - Prepare well for DSA and System Design.

Stay confident.

For System Design and OOD, always clarify the requirements since it's very open-ended and subjective. And do keep an eye on the clock.