# Byju’s Interview Coding Questions for Backend Engineer (SSE)

Hi, I’m sharing my Byju’s interview coding questions for backend engineer, Senior Software Engineer (SSE). My profile was shortlisted from the Naukri and HR scheduled the interview.

This interview was for experience candidate. Each interview was scheduled for one hour on Google Meet.

### Round 1: Byju’s Interview Questions for SSE

Initially we started with introductions and then he asked me some questions related to my current project as below.

• How can you check the performance of the API?
• How microservices are different from service-based architecture?

Coding question 1: Minimum coin require to match the given amount.

You have given a set of coins. Write a program to find the minimum number of coins required to match the given amount value.

```You have coins 1, 5, 7, 9, 11. Calculate minimum number of coins required for any input amount 250.

Example:
AMount 6 will require 2 coins (1, 5).
Amount 25 will require 3 coins (5, 9, 11).```

You will be given 30 minutes to solve this coding question.

I heard, one of the other members was asked different questions.

Coding question 2: Write a program to merge the overlapping intervals.

After answering all these questions, I was asked for a second interview with the Senior Software Backend Engineer.

### Round 2: Coding Interview Questions

We had a discussion about my current project which is based on the REST APIs. So he asked me some questions on REST APIs related to my projects.

Some questions that I can remember:

• Rollback mechanism in case of failure.

#### Coding Questions

Question 1: You have given a rotated sorted array. Find the two pairs having sum ‘k’.

Solution:

• Initially, you have to sort the circular rotated array. This can be done in `O(n)` time.
• Then, find two numbers in the sorted array having sum ‘k’.

You have to be very good at coding. So, before intending the interview, I would recommend you to practice solving competitive coding challenges.

Question 2: Logical Question on Credit Card Pattern Matching

You will be given the criteria to distinguish three credit cards Visa, MasterCard, and American Express as below.

```Visa: All Visa card numbers start with a 4. New cards have 16 digits. Old cards have 13.

MasterCard: MasterCard numbers either start with the numbers 51 through 55 or with the numbers 2221 through 2720. All have 16 digits.

American Express:  American Express card numbers start with 34 or 37 and have 15 digits.```

What approach you will follow?

Note: You don’t need to write a program for this. You have to tell them your approach to solve this. Tell the interviewer as we can write a regular expression for these pattern matching.

I heard some of the candidates were asked for the below questions.

Question 3: Design data structure for many-to-many relationship

You are giving a list of students and a list of courses. This is a many to many relationships. You will be given queries to answer according to this. You have to design a data structure to store the relation.

Answer: To resolve the many-to-many relationship, you have to create three different classes or tables. One is for “students”, the second is for “courses” and the third can be “enrollment”. Later one will preserve the relation between students and courses. Here, you also have to explain the primary and foreign key mechanism.

That’s all from my interview experience. All the best!

Editors’ note: This experience and Byju’s interview coding questions for backend engineer shared by the candidate Navin. We wish him all the best for his future.