Swiggy SDE 1 Interview Experience | Backend Engineer | Bangalore

I applied for the SDE 1 Backend Engineer role at Swiggy through a referral. The interview process consisted of four rounds, covering DSA, Java, Spring Boot, low-level design, and project discussions.

Round 1: Online Assessment (OA)

The online assessment consisted of three medium-level coding problems:

• Longest Substring Without Repeating Characters - Find the length of the longest substring containing no repeated characters.

• Network Delay Time - Given a weighted graph, determine the minimum time required for a signal to reach all nodes.

• Find the Integer Nth Root - Given two integers, find the integer nth root of a number if it exists.

Round 2: DSA + Java and Spring Boot

This round was conducted through a third-party interview platform.

DSA Question

Count the Number of Unique Binary Search Trees

Given an integer (n), determine how many structurally unique binary search trees can be formed using values from 1 to (n).

I discussed both the brute-force approach and the dynamic programming solution, explaining the recurrence relation and complexity.

Java and Spring Boot Questions

The interviewer also asked questions related to Java fundamentals and Spring Boot:

• What is the difference between an interface and an abstract class in Java?

• How does Java handle exceptions, and what is the difference between checked and unchecked exceptions?

• How does the final keyword work in Java?

• What is the purpose of @RestController in Spring Boot?

• How does Spring Boot manage application configuration?

• What is the role of the Spring Bean lifecycle?

Round 3: Low-Level Design (LLD)

I was asked to design a food ordering system with basic functionalities such as browsing restaurants, adding dishes to an order, calculating the bill, and applying different offers or discounts.

I started by clarifying the requirements, constraints, and expected behavior before discussing the design.

For handling different discount strategies, I used the Strategy Design Pattern, which made it easier to introduce new discount rules without changing the core ordering logic.

I also discussed the main classes, their responsibilities, and how the design could be extended with additional features. The interviewer was engaged throughout the discussion, making it a good interactive round.

Round 4: Hiring Manager (HM) Round

The final round began with an in-depth discussion of my current project.

We covered topics such as:

• Project scope, requirements, and implementation choices.

• Production issues I had encountered and how I resolved them.

• What I could have done differently to prevent or reduce the impact of those issues.

• SQL queries, indexing, and database performance.

• Rating myself on the technologies in my current tech stack.

• Why I wanted to join Swiggy.

• Behavioral and situational questions.

I was also asked a dynamic programming question:

Coin Change II

Given a set of coin denominations and a target amount, find the number of distinct combinations that can be used to make that amount, assuming each denomination can be used unlimited times.

I discussed the dynamic programming approach and how to avoid counting the same combination multiple times.

The hiring manager also explained his team's work and gave me an idea of the technologies I might work with if selected.

After the interviews, I received a call from HR confirming my selection.

I hope this helps others preparing for Swiggy's SDE 1 Backend Engineer interviews.

All the best.