Sigmoid Interview Questions
& Process

This was an on-campus drive for Sigmoid Analytics. It started with an Online Assessment (OA) that had 8 medium-level coding questions and MCQs on core CS subjects like OS, DBMS, and aptitude. Then there were 3 interview rounds: 2 technical and 1 HR. The first two rounds were virtual, and the third was offline. Round 1 focused on resume projects (backend CORS policy), DSA (valid anagrams, climbing stairs with DP optimization, minimum insertions for palindrome), coding on a compiler with test cases, and an easy SQL query. Round 2 delved into OOPs concepts (runtime vs. compile-time polymorphism) due to C++ skills, and more DSA (top K frequent elements, delete Nth node from linked list, BST pairs summing to K). Round 3 was all about project architecture explanations, a SQL query for the second highest value, differences between SQL and NoSQL, advice on DB choice, and scaling concepts (vertical/horizontal).

There were 3 interview rounds plus a written test. Round 1 focused on resume and project questions. Round 2 covered technical topics like Python, Power BI, and SQL. Round 3 was with the manager, including some behavioral and technical questions, though the manager seemed disengaged, joining late and leaving early, cutting the interview short. Despite the time invested in the interviews and written exam, there was no follow-up regarding the results, which was frustrating as similar experiences were reported by others in my network. This lack of professionalism and communication was disappointing.

Sigmoid's hiring process has a few steps to check if you have the technical skills, can solve problems, and fit in. It can differ based on the job and how much experience you have. Usually, it starts with an online test. This test has multiple-choice questions and coding problems. One person said they had a 1.5-hour test with five MCQs on quant and tech stuff, and five coding questions that were not too easy, not too hard. Then, if you pass, you go to technical interviews, which might be more than one round. They check your knowledge of data structures, algorithms, and how you solve problems. For example, you might get asked to reverse a linked list in specific group sizes or do a zigzag tree traversal. For data analyst roles, you might also get tested on statistics, machine learning, SQL, and tools like Tableau for visualizing data. The last part is usually an HR interview where they talk about your past work, why you want the job, and if you match the company's vibe.

I found this opportunity on Naukri, and they had to reschedule the interview three times. On the third attempt, the interviewer showed up, even though they were five minutes late. They started with introductions, then asked me to print the bottom view of a BST, but they seemed unclear about the test cases themselves and took about 35 minutes just to explain the problem. When I told them I wasn't clear on the problem, they asked me to find the cycle in a linked list. In the last 10 minutes, I gave an approach, but I knew it wasn't correct. I didn't really care though, as I was already fed up with the interviewer and just wanted to end the call.