Prashant KUMAR
Which clg
My Sigmoid Interview Experience on Campus
October 24, 2025 • 47 reads
Summary
I recently interviewed for the Software Development Engineer (SDE) role at Sigmoid during their on-campus recruitment. Although I successfully navigated several technical and managerial rounds, I ultimately received a rejection after the final round. Despite the outcome, the entire interview process proved to be a significant learning experience for me.
Full Experience
I had the opportunity to interview with Sigmoid for the Software Development Engineer (SDE) role during their campus recruitment drive. The process was structured into four distinct rounds, and while I wasn't ultimately selected, it was an incredibly valuable journey that sharpened my technical and problem-solving skills.
Round 1: Online Coding Test (2 hours)
The first hurdle was an online coding test lasting two hours. This round was comprehensive, divided into three sections:- Section 1: 8 Data Structures and Algorithms (DSA) problems.
- Section 2: 15 Computer Science Fundamentals questions.
- Section 3: 15 Puzzles & Aptitude questions.
Round 2: Technical Interview (80 min)
My second round was an 80-minute technical interview. The interviewer delved into both DSA and core CS concepts:- I was asked to solve DSA problems like Decode String (LeetCode 395), Three Sum (LeetCode 15), and Longest Substring Without Repeating Characters (LeetCode 3).
- We discussed the fundamental pillars of OOPS.
- Questions on various HTTP status codes were posed.
- A system design discussion covered topics such as load balancing, horizontal vs. vertical scaling, and SOLID principles.
- Finally, I had to explain the key differences between Python, C++, and Java.
Round 3: Technical Interview (40-50 min)
The third technical interview was shorter, lasting about 40-50 minutes, and primarily focused on coding:- I was asked to code a solution in VS Code to 'Build Tree From preorder and postorder'.
- Another coding challenge in VS Code was to 'find minimum Cost in Grid' using dynamic programming.
Round 4: HR + Managerial Round (approx 70-80 min)
The final round was a combined HR and Managerial interview, lasting approximately 70-80 minutes. This round assessed both my soft skills and project-specific technical depth:- I started with a self-introduction.
- I was given a medium-to-hard level SQL query to solve.
- We had an in-depth discussion about my projects.
- A significant part involved drawing the architectural diagram of one of my projects on paper, explaining how it works, how each component is connected, and their behavior and interaction.
Verdict: Rejected
Unfortunately, despite making it to the final round, I was not among the 6 students selected for the role. Although I didn't get the offer, the process was a fantastic learning opportunity that helped me understand the interview landscape better and hone my skills.Interview Questions (13)
Q1
Decode String
Data Structures & AlgorithmsMedium
Q2
Three Sum
Data Structures & AlgorithmsMedium
Q3
Longest Substring Without Repeating Characters
Data Structures & AlgorithmsMedium
Q4
OOPS Pillars
Other
The interviewer questioned me about the fundamental pillars of Object-Oriented Programming (OOPs), such as encapsulation, inheritance, polymorphism, and abstraction.
Q5
HTTP Status Codes
Other
I was asked to explain various HTTP status codes and their meanings, including examples for different categories like informational, success, redirection, client error, and server error.
Q6
System Design: Load Balancing and Scaling
System Design
I discussed system design concepts including load balancing techniques and the differences between horizontal and vertical scaling. I also touched upon SOLID principles in software design.
Q7
Differences between Python, C++, and Java
Other
I was asked to explain the key differences and use cases for programming languages like Python, C++, and Java, discussing aspects such as memory management, execution speed, and paradigms.
Q8
Construct Binary Tree from Preorder and Postorder Traversal
Data Structures & AlgorithmsHard
In VS Code, I was tasked with building a binary tree given its preorder and postorder traversals. This involved reconstructing the tree structure based on the order of node visits in both traversals.
Q9
Minimum Cost Path in a Grid (DP)
Data Structures & AlgorithmsMedium
I was asked to solve a dynamic programming problem in VS Code: finding the minimum cost path to reach a specific cell in a grid, given movement rules and associated costs.
Q10
Self Introduction
Behavioral
I was asked to introduce myself, covering my background, education, and professional aspirations.
Q11
Medium-to-Hard SQL Query
OtherMedium
I was given a medium-to-hard level SQL query to write, likely involving joins, subqueries, or aggregate functions, to extract specific data from a hypothetical database schema.
Q12
Project Discussion
Behavioral
I discussed my past projects, highlighting my role, the technologies used, challenges faced, and outcomes.
Q13
Project Architectural Diagram and Explanation
System Design
I had to draw an architectural diagram of one of my projects on paper, illustrating its components, their connections, and explaining their behavior and interactions.