Duration: 90 minutes Difficulty: Hard Platform: HackerEarth Desktop
The first round consisted of 4 coding questions.
A problem based on splitting an array while optimizing the maximum subarray sum.
A graph problem involving node colors and minimum cost.
A dynamic programming problem involving people, scores, and passing criteria.
Given arrays A and B, the task was to find the most "sad" permutation of A based on the given conditions.
Round 1 Result
There were 181 candidates, out of which 18 candidates were shortlisted for the next round.
Question for practice : https://www.codinzhub.com/question/energy-channel-optimization-phonepay-online-assessment-mnnit-allahabad
https://www.codinzhub.com/question/prerajuisation-numbers-phonepay-online-assessment-mnnit-allahabad
Duration: 60 minutes Difficulty: Hard
Two DSA problems were discussed.
The interviewer asked about the Burning Tree problem.
The candidate first explained and implemented the BFS approach, followed by the recursive DFS approach.
The discussion focused on understanding the tree traversal and explaining the approach clearly.
The candidate initially explained the brute-force approach and then optimized it using a stack-based approach with O(N) complexity.
Round 2 Result
11 out of 18 candidates were shortlisted for the next round.
Duration: 60 minutes Difficulty: Hard
The interviewer asked the candidate to generate all valid combinations of balanced parentheses.
The candidate explained and implemented the recursive/backtracking approach.
A dynamic programming problem was discussed.
The candidate explained the complete approach and the DP state, but could not complete the implementation within the given time.
Round 3 Result
5 out of 11 candidates were shortlisted for the final round.
Duration: 70 minutes Difficulty: Hard
The final round combined HR, project discussion, CS fundamentals, puzzles, and technical questions.
The interviewer asked questions such as:
Why PhonePe? Why not Google or Amazon, which offer higher packages? What made you choose PhonePe?
The discussion focused on the candidate's motivation for joining PhonePe and understanding of the company.
Django REST Framework Project
Puzzle
A puzzle involving 12 rats, 4 cakes, and different eating speeds was discussed.
The candidate developed a solution that worked for up to 36 rats, but the interviewer asked them to explain the complete solution in greater detail.
This round tested the candidate's ability to reason through a problem and communicate the solution clearly.
CS Fundamentals
The interviewer asked several core computer science questions, including:
Difference between Stack Memory and Heap Memory What is Inheritance? What is a Virtual Function? What is a Class in C++? What is Deadlock? What are the conditions required for a deadlock?
DBMS + System Design
The candidate was asked to design a lift system for a building with 1,000 floors.
Multiple approaches were discussed using different:
Data structures Virtual classes Maps System design concepts
The discussion focused on how the candidate would structure the system and choose appropriate data structures and abstractions.
Final Result
After completing all four rounds:
4 candidates were selected for 6m+PPO offer. later on 2 more candidates for 6m+FTE offer.
Key Takeaways
The PhonePe interview process was heavily focused on DSA, problem-solving, communication, and CS fundamentals.