Zeta

Role: SDE-1 (Backend)

College: Not Specified

Interview Date: Not Specified

Interview Type: Full-Time

Result: Not Specified

Difficulty: Medium to Hard

Rounds: 3 rounds

Topics Asked: Data Structures and Algorithms, Problem Solving, Object-Oriented Design, Caching, Operating Systems, DBMS (CAP theorem, ACID properties), Networking (TCP/IP, UDP), Race Condition, Thread Synchronization, Multithreading, JavaScript (Node.js concurrency, Event Loop), Java OOPs (Overloading, Overriding, Functional Interface, Access Specifiers, Abstraction, Abstract Class vs Interface, 'super', 'static', 'final' keywords, Constructor 'final'), SQL vs NoSQL

Experience:

The candidate applied for an SDE 1 (backend) position at Zeta (Directi) through a referral. After a week, a call from the talent acquisition team involved behavioral questions, technologies worked on, self-rating in DSA, and other technical questions. There was no online test in the hiring process. In total, there were 3 rounds of interviews.

Round 1: DSA and Problem-Solving Round

The interviewer asked two DSA questions. The first involved finding the maximum difference between two elements in an array (a[j] - a[i] where j > i). The candidate initially proposed a brute-force approach (O(n^2)), then optimized it using a prefix array, and finally achieved a constant space and linear time solution. The second question was about partitioning a given string of 'A's and 'B's into two parts such that the number of 'A's in the first part equals the number of 'B's in the second part. The candidate discussed a brute-force approach using backtracking and was asked to optimize it further.

Round 2: Technical and Object-Oriented Design Round

This round started with a discussion on the candidate's projects. Questions were asked regarding multithreading. As the candidate used JavaScript in projects, questions on Node.js concurrency and the event loop were posed. The interviewer then asked a design question related to implementing a cache. The candidate had to come up with the logic for putting and getting elements from the cache and then code the entire class. The interviewer also tested knowledge of OS, DBMS, and networking. Specific questions included:

• What are the CAP theorem and its significance?
• Explain TCP/IP and UDP protocols along with their differences.
• Explain ACID properties in transaction management.
• What is a race condition? What are the reasons for its occurrence and how to deal with it?
• How to achieve thread synchronization?

Additionally, Java OOPs concepts were covered:

• Difference between method overloading and overriding?
• What is a functional interface and how many methods can exist in that?
• Explain the access specifiers in Java.
• What is abstraction?
• Differences between abstract class and interface?
• Explain 'super', 'static', and 'final' keywords in Java.
• Can a constructor be 'final' in Java? Explain.
• Differences between SQL and NoSQL databases?

The interviewer was satisfied with the approaches and coding.

Round 3: Fitment Round

The details of this round are not explicitly provided in the snippet beyond it being a "Fitment round" and the overall process having three rounds.

Suggestion: The candidate advised speaking out thoughts while coding and communicating properly to receive hints if stuck, as the interviewer judges the thought process.