Juspay Interview experience On campus for sde intern

I recently had the opportunity to participate in the Juspay SDE Intern hiring process during the summer. It was a challenging yet insightful experience consisting of six rounds. Unfortunately, I couldn’t make it through the final round, but I learned a lot through the process. Here’s a detailed breakdown of my experience:

Round 1: Aptitude Test (Online)

This round had about 300 candidates and lasted 1 hour. It covered OS, CN, Math, and DSA fundamentals. I needed 50% marks to qualify, and the questions were straightforward but required quick thinking.

Round 2: DSA Round

Approximately 180 candidates moved to this 3-hour DSA round. The topics focused on Trees, Graphs, and Strings, with 3 questions in total. I managed to solve two questions out of three (needing 200/300 marks) which helped me qualify for the next round.

Round 3: Hackathon (Part A)

Around 35 candidates participated in this 3-hour hackathon. The main task was to implement Lock, Unlock, and Upgrade functions on a tree structure. It was quite challenging, requiring both efficient and logically sound solutions.

Round 4: Elimination Round (Anti-Cheating Verification)

With about 23 candidates remaining, this 2-hour round served as an integrity check. I had to share my screen and keep my camera on while solving two questions on Hashing and Backtracking. Both questions were of moderate difficulty and required careful thought.

Round 5: Hackathon (Part B)

This was by far the most difficult round, lasting two days for me, though it's usually a single day. Roughly 13 candidates made it here. The tasks included explaining my solution from Part A, improving its time complexity, and implementing a thread-safe solution without using external libraries or atomic variables. Debugging, optimizing, and ensuring thread safety under these constraints truly tested my problem-solving and coding skills under pressure.

Round 6: System Design + Technical Interview

Only about 9 candidates reached this final 2-hour and 15-minute round. It covered OS, CN, CNS, and System Design. The questions were highly conceptual and challenging, probing deep knowledge and optimization techniques. The specific questions I faced were:

1. How does YouTube differentiate between requests from:
   • Two tabs playing YouTube on the same laptop
   • Two different laptops on the same network
   • Two laptops connected to different Networks
2. How are files uploaded to Google Drive and shared between two systems?
3. Compiler vs Interpreter — I was asked to improve the runtime of the following interpreted language code:

   Function f(int c) {
       c++;
       print(c);
       return c;
   }
   main {
       int c=0;
       for(int i = 0; i < 1000; i++) c = f(c);
   }
   

   (The hint provided was that the function call is redundant and can be cached to improve performance).

I felt the questions in the final round were a bit tougher compared to my peers, but it was a great learning experience. This process helped me identify areas for improvement, especially in system design and optimization. I'll work on strengthening these areas and come back stronger next time!