Amazon Interview Experience for SDE Role | 6-Months Internship + PPO (On-Campus)

Amazon arrived for hiring in the last week of July 2021 on our campus for the Software Development Engineer Role. We had a total of 3 rounds (1 Online Coding on Amazon’s Assessment Portal + 2 Technical Interviews).

Here is my interview experience for the same.

Round 1(Online Coding Round): This round was conducted on Amazon’s own Assessment platform, There were MCQs on Aptitude, Basic Programming, CS fundamentals, English Comprehension, and Decision Making along with 2 coding questions of easy/medium difficulty.

• Suggestion for MCQs: Have a sound Knowledge of CS Fundamentals and Aptitude Solving Practice.
• Coding Questions were based on Implementation only.
• Good practice on Implementation based problems involving Maps, Vectors, Sets, and other C++ STL components is a must.

Round 2(Technical Interview 1): The platform for the Interview was Amazon Chime

The Interviewer asked only 2 Coding Questions in this round:

1. The first problem was, Given an array of size n having n elements and another array of size n+m having m elements, Sort these two arrays and store the final result in the second array, which should contain the elements of both the arrays.
   • First I suggested a Brute Force solution by using a third array and then sort them and put them back in the Second array.
   • After that, I suggested a better solution without using a third array, by comparing elements from starting of the first array to the elements at the starting of the second array.
   • After that, he said you are close and then gave me a hint, and I was able to solve the problem successfully.
   • After that, I was asked to code the solution for this problem, which I did as well.
   • And then I was asked to determine the Time and Space Complexity of my code.
2. The Second Problem was, Given a Binary Search Tree, Convert it into a Sorted Doubly Linked List and return the Head Pointer.
   • This was a Standard Problem of BST.
   • I explained my Approach by Traversing from the right to left in the Tree to get the Sorted order of the Linked List.
   • And then I wrote the code for My solution.
   • The interviewer was satisfied with my Code and then asked me to determine the Time and Space Complexity of my code.

After this, he asked if I had any questions for him. This round lasted for about 60 Minutes.

Round 3 (Technical Interview 2): The platform for the Interview was Amazon Chime

The Interviewer asked 2 Coding Questions and some Behavioural Questions in this round :

1. The first problem was, Find the first 100 Prime Numbers.
   • For this Problem first, I suggested a Brute Force Approach by checking numbers starting from 2 whether they are Prime or Not, till we get 100 Prime Numbers.
   • After that, I suggested a better approach, which is using the Sieve of Eratosthenes Algorithm.
   • He was satisfied with my Approach, after that he made me code the Solution.
   • After that, he asked me the Time and Space Complexity of my Code.
2. The second problem was, Given an array of Strings, find which strings can be combined with other strings in the array so as to make the strings that are present in the array.
   • For this Problem, First, I suggested a Brute Force Approach using Maps.
   • After that, he asked me for a better approach.
   • After Thinking a while, I figured out another Approach using Trie.
   • He asked me to explain the Concept of Trie Data Structure and why do we use it.
   • After that he asked me to code the solution using Trie.
   • After I completed the code, he asked me the Time and Space Complexity of my Code.
   • I was, to give the proper logic and explain my approach to him and he was satisfied with my Solution.

After this, he asked me some Behavioural Questions which are the Important Part of all the Amazon Interviews. Fortunately, I had already prepared for some of the Most asked Behavioural Questions by Amazon. The behavioral questions were,

1. What is the most innovative thing you have done?
2. When is the time when you tried something unique, Did you failed or succeed?

After this, he asked if I had any questions for him. This round lasted for about 65 Minutes.

After around 1.5 Weeks, the Result was declared and I was selected for the role of Software Development Engineer (6-Months Internship + PPO).

My suggestion for the Interviews :

1. Practice all the Standard Amazon problems from GfG.
2. Have a good understanding of the CS Fundamentals in OS, DBMS, CN, and OOPS.
3. Prepare some short notes on CS fundamentals and DSA Problems, which will we useful for last-minute revision.
4. Prepare and notes down answers to some Standard Amazon Behavioural round questions :
   • Tell me about Yourself.
   • What are your Strengths and Weaknesses.
   • Tell me about a hard situation for you, and how did you overcome it.
   • Tell me about a time when you took a risk and failed.
   • Why should we hire you.

At last, always keep calm while giving the Interviews for positive results.

All the best for your Interviews.