Amazon Interview Experience for SDE Internship
I attended the pool drive in a college where students from different colleges were present.
There were 3 rounds- online round and 2 technical face to face interview rounds.
Online round: There were 28 MCQS and 2 coding questions. MCQs were mostly on data structures, C/C++ outputs, and 3 aptitude questions.
The two coding questions were:
- Given a string input in the format “num1+num2=num3”. One of the numbers will be given as ‘X’ (eg: “5+X=9”). Return the value of X.
- Given a string input in the format “ar ar2” (eg: “9 27”) which are 2nd and 3rd numbers in Geometric progression. Given n, return nth value of that Geometric progression.
There were around 80 people waiting for an interview from 4 different colleges.
Technical round 1:
The interviewer started by asking about the projects I had done. I explained the recent project I did. He then started asking questions about implementations of some things in my projects. I was asked to write database schema, queries that I used in my web application. I used the firebase database in my android application. He asked a few questions about the storage and retrieval of data in firebase and also the difference between SQL and NoSQL databases and about which one’s the most preferred. I answered them.
He then asked a few questions about cache memory in web browsers and also to write the code in my C compiler project. The questions about my projects went on for 45mins.
Then I was given a simple coding question.
- Find the missing number in an array where the numbers are consecutive and but in an unsorted manner.
I explained my two approaches. He then asked me to write the code for that (You are free to write code in any language unless the interviewer mentions otherwise).
After the first technical round around 30 people were shortlisted for technical round 2.
Technical round 2:
This was completely coding round. He asked optimal solutions for all the questions and write the code.
The questions were:
- Find the intersection point of 2 linked lists.
- Print right view of the binary tree.
- Given a lake starting at 0, ending at 1 and list of drops in the pairs (x, r) where x is the point that the drop falls on the lake and r is the radius of the ripple caused in the lake due to that drop. Find the minimum number of drops required to cover the entire lake with ripples.
The interviewers in Amazon are really chilled out and you can freely interact with them. They’ll even help you if you get stuck anywhere in answering their questions.
After the interviews were done, 4 were selected for SDE role (fortunately I was one of them), 3 for Data Engineer role and 8 for Support Engineer role, out of the 80 that attended the interviews.