PubMatic Interview Experience for SDE (On-Campus)

Round 1:

In total, there were 17 questions: 15 multiple-choice questions (MCQs) and 2 coding questions. A total of 211 students participated and only 20, including myself—were selected for subsequent rounds.

Before the technical interview, candidates were asked to specify their top 3 preferred programming languages Scala, Java, JavaScript, and C.

Round 2 (first technical interview):

The interviewer was friendly and started with the following questions:

• Self-introduction.
• Explanation of my final-year group project.
• In-depth questions about the project, including my role and the distinctions from existing applications.
• An explanation of the four pillars of object-oriented programming (OOPS).
• There are differences between abstract classes and interfaces.
• Questions related to hashmap.

DSA-related problems, such as

• finding the first subarray with a sum equal to the target
• deleting the last node in a linked list with a target value.

Questions on joins.

• SQL query to determine the second-highest salary in a table.

The interview lasted for an hour, and some candidates, including myself, progressed to the second technical round.

Round 3 (Second Technical Interview):

The second technical interview encompassed the following topics:

• Self-introduction.
• Project explanation, similar to the first round.
• Detailed questions about encapsulation and abstraction, with real-life examples.
• Inquiry into why strings are immutable.
• An in-depth discussion on the internal workings of hashmap.
• DSA question involving decoding strings.
  Input Output
  [a2[b]] : abb
  2[b3[a]]] : baaabaaa
  3[a2[b]] : abcbcabcbcabcbc
• Clarification of concepts such as program, process, and thread.
• Definition of deadlock, along with conditions for deadlock avoidance.
• Explanation of semaphores.
• SQL query to determine the number of distinct employees.

The interview spanned 1 hour and 20 minutes, and only three candidates, myself included, progressed to the HR round.