Pubmatic

Role: SDE (Software Development Engineer)

College: Not Specified (On-Campus)

Interview Date: October 9, 2024

Interview Type: On-Campus, Full-Time

Result: Not Specified

Difficulty: Not Specified

Rounds: 3 rounds

Topics Asked: MCQs (core subjects), C/C++, Java, Scala, JavaScript, OOPs, DBMS, OS, Networking, Data Structures, Algorithms, Project Discussion, Hashmap, String Immutability, Program/Process/Thread, Deadlock, Semaphores, SQL.

Experience:

PubMatic conducted an on-campus recruitment drive.

Round 1: Online Assessment
This round consisted of 17 questions: 15 multiple-choice questions (MCQs) and 2 coding questions. The MCQs covered core subjects like C/C++, Java, OOPs, DBMS, Linux, and Computer Networks. Candidates were asked to specify their top 3 preferred programming languages (Scala, Java, JavaScript, C) before the technical interviews. Out of 211 students, 20 were selected for subsequent rounds.

Round 2: First Technical Interview
The interviewer started with a self-introduction and then asked for an explanation of the final-year group project, including the candidate's role and how it differed from existing applications. Questions on Object-Oriented Programming (OOPs) included the four pillars of OOPS and the differences between abstract classes and interfaces. Hashmap-related questions were also asked. Data Structures and Algorithms (DSA) problems included finding the first subarray with a sum equal to the target and deleting the last node in a linked list with a target value. SQL questions involved joins and a query to determine the second-highest salary in a table. This round lasted for an hour.

Round 3: Second Technical Interview
This round also started with a self-introduction and project explanation. Detailed questions were asked about encapsulation and abstraction with real-life examples, and why strings are immutable. There was an in-depth discussion on the internal workings of a hashmap. A DSA question involved decoding strings, with examples like `[a2[b]]` outputting `abb`, `2[b3[a]]` outputting `baaabaaa`, and `3[a2[b[c]]]` outputting `abcbcabcbcabcbc`. Concepts like program, process, and thread were clarified, along with the definition of deadlock and conditions for deadlock avoidance, and an explanation of semaphores. An SQL query to determine the number of distinct employees was also asked.