Squad Stack

Role: Product Engineer

College: Not Specified

Interview Date: July 23, 2025

Interview Type: On-Campus Placement Drive

Result: Not Specified

Difficulty: Not Specified

Rounds: 6 rounds

Topics Asked: Aptitude, Logical Reasoning, Data Structures, Algorithms (Inversion Count, Implementation, Graphs, Duplicates in Array, Basic Calculator II), DBMS (SQL vs NoSQL, Normalization, Denormalization, CAP theorem, PostgreSQL), Computer Networks, Operating Systems (Race condition, Deadlock), OOPs (NULL/Dangling Pointers, Call by value/reference, abstract classes, API Calling, Typecasting, Compile-time polymorphism, Runtime polymorphism, Static and Dynamic programming languages), System Design (Instagram features, schemas, server design, load balancers), Behavioral.

Experience:

This candidate applied through an On-Campus Placement Drive, and all 6 rounds were conducted online due to COVID.

Round 1 (Aptitude Test): This round consisted of 100 MCQs covering Aptitude and Logical Reasoning. There was no negative marking.

Round 2 (Coding Test 1): After clearing the first round, a link for coding questions was sent. There were 4 questions, with choices in 2 of them, requiring the candidate to attempt 3 questions. Topics included Inversion Count, two implementation-based questions, and one on graphs.

Round 3 (Coding Test 2): This round was another coding assessment. It included 10 MCQs on PostgreSQL, DBMS, and Computer Networks, along with 2 graph questions that were medium to hard level.

Round 4 (1st Interview -> Tech Deep Dive + Coding Round): This round lasted approximately 1.5 hours. It started with basic questions from CS subjects such as the difference between SQL and NoSQL, normalization and denormalization, Authentication and Authorization, CAP theorem, Race condition, Deadlock, NULL/Dangling Pointers, Call by value/reference, abstract classes, API Calling, Typecasting, Compile-time polymorphism, Runtime polymorphism, Static and Dynamic programming languages. General questions about databases worked upon (SQL or NoSQL) were also asked. Following this, two coding questions were given: one similar to finding duplicates in an array (e.g., GeeksforGeeks problems) and another similar to implementing a basic calculator II (e.g., LeetCode problem).

Round 5 (2nd Interview -> Bar Raiser/Design Round): This was a System Design Round, lasting about 1.5 hours. The interviewer asked the candidate to design the basic features of Instagram and its necessary schemas. The candidate had to think of tables like User Login, Posts, etc., and discuss each step with the interviewer, including fields, primary/foreign keys, and data types. Questions were also asked about servers needed for the design and how to handle a database with millions of records and 1000 queries per second, suggesting knowledge of Load Balancers is important. The candidate suggested practicing DBMS concepts and SQL queries like ORDER BY, WHERE, TOP, and subqueries.

Round 6 (3rd Interview -> Culture Fit Round): This round lasted 30-35 minutes and focused on behavioral questions. Questions included "why you want to join us," "why you selected engineering," and "if you are given 3 offers from different big companies then which one would you choose, and why." The same question was then posed for startups. The candidate was also asked about the most challenging problem faced and how it was tackled, and which interview round was the best. The interviewer concluded by asking if the candidate had any questions.