PhonePe Interview Experience for Software Engineer 2023

Every year on August 1st, PhonePe visits our campus (Pune Institute of Computer Technology) to hire students for the role of software engineering. The offer included both Full-Time Employment (FTE) and an internship, with the job location specified as Pune. The hiring process had 4 rounds, all of them on the same day, along with the results. 

Eligibility Criteria:

• 10th and 12th: 50% and above
• CGPA: 6 and above (no active backlogs)
• Dream Criteria: It depends on the college if they need to filter out students; we had Amcat criteria.

After the Amcat filter, about 370 students were eligible for the offline Coding Assessment.

Round 1 (offline Coding Assessment):

• It consisted of four questions and 90 minutes.
• The first question was related to binary search and was easy-medium in difficulty (Codeforces 1300 to 1400 rating).
• The second question had two sub-tasks and was based on trees and expected value calculations.
• The third question was based on dynamic programming.
• I am not aware of the fourth question.

I was able to solve the first question (all test cases) and the second question partially (7/13 test cases).

The difficulty for sub-task 1 of Q2 would be 1500 to 1700 (code forces).

The real challenge was not solving the question but understanding how the output is being generated; there was no explanation given to the test cases, and it took a lot of time to figure it out.

After Round 1, were eligible for the interviews, and I was one of them.

Round 2 (Technical Interview):

It consisted of two coding questions, and the interviewer was friendly and supportive.
After my introduction, we started solving the questions.

1) Find the min or max frequency element, given the following operations :

• Add an element.
• Remove an element.
• Find the minimum frequency element.
• Find the maximum frequency element.

I was able to solve this question using a hashmap; it seems to be a typical Leetcode medium question.

2) Calculate the minimum cost of the journey from n1 (int) to n2 (int), where the cost of the journey from one prime number to another was their difference (we can't go from non-prime to non-prime even by spending money). For any number, if we reduce that number by taking the sum of its digits until we get a single-digit number, if this single-digit number is prime, then the cost of the journey from that number to the single digit would be zero (in both directions).
Example: For 785, we can reduce it to 785->20->2, which is a prime, so we can go from 2 to 785 (and vice versa) at 0 cost.
If it is not possible to move from n1 to n2, print -1.

I was able to solve this question; it was a medium-level difficulty question.

This round lasted about 35 to 40 minutes.

I am not aware of how many students were rejected in Round 2 but I was fortunate enough to get selected for Round 3.

Round 3 (Technical Interview):

It had the same format as Round 2, consisting of two coding questions, and the interviewer was friendly and supportive.

1) There are m breads with costs [b1, b2, b3,..., bm] and n sauces with costs [s1, s2, s3,..., sn], and we are given a budget B. Choose exactly one bread and any number of sauces at most once, and make the bill as close as possible to the budget B.

• I was able to solve this using a 0/1 knapsack.
• The interviewer told me to draw the tabulation and explain to him a test case.
  I filled the whole DP table in front of him.
• He asked me about the algorithm to get what sauces were used. I was aware of how to do that, and he was impressed.

After this question, he told me, Let's now solve a problem you haven't seen before. I became a bit nervous (again, he was iitian)

2) Given an array, perform either +k or -k exactly once for every element of the array such that the difference of the max and the min was minimum after the operations.

I was not able to crack this question, but the interviewer gave me some hints, and he even tried to give me hints by plotting the points. This was really helpful for me, and then I was able to solve this question.

I Think solving a question is not that important, but solving it collaboratively with the interviewer is what they look for.

This round too was for 35 to 40 minutes.

Round 4 (Techno-hr Round):

This round consisted of a deep discussion about the projects and also some typical hr questions.

I just had in mind, to be honest with the interviewer.

The following questions were asked of me in this round :

1. Why and with whom did you have your recent argument, and how did you deal with it?
2. What real-world problems have you solved other than programming?
3. What are other domains other than tech that you like? (I am pretty good in the finance domain.)
4. discussed the internship I did in my second year (he even checked the repository).
5. We participated in Namma Yatri Open Mobility Challenge and made an app-less ride booking solution using telegram so the following questions were asked :
   1) What all happened during the hackathon? like why this topic, why telegram, how to create a bot, and stuff.
   2) He then tested the bot and hopefully, it was working well.
   3) We were a team of three for this challenge so he asked me, How did you merge all your work? I told him it was done by one of my team members, as he was good in Git.
6. Asked some questions about React.js :
   1) what is virtual dom?
   2) What are all the hooks you know? 
   3) Differences between use effect and use state hooks
   4) What was my greatest learning curve while learning to react?
7. I had a project in Django, so he asked me which language is used in Django :)
8. What are the new technologies or concepts you like?
   1) I am a fan of the concept of ONDC since my second year (i explored it a lot!!)so i told him that, and he introduced me to Pincode, an ONDC-based app by PhonePe.
   2) Where did you, for the very first time, learn about or hear about ONDC? ( i told him about the ThinkSchool Youtube channel )
9. How is polymorphism shown by smartphones and what is polymorphism?
   I told him that a phone can take the form or role of a music player, alarm, videogame, timer, and many more.
10. Some questions related to MongoDB
11. What if the backend is sending {x,y} data but the frontend requires {x,y,z} ? How would you handle that?
    I told I will handle the null value in my front, then he introduced me to the concept of API Contracts.
12. Asked questions on the work done in college events
13. Have you worked on any project where one team focused on the backend and other on the frontend ? 
    

This round continued for about 40 to 45 minutes.

After Round-4, 3 students out of 8 were selected, and I was one among them!!!!

It was indeed a great experience!

I did prepare for core subjects for PhonePe :

• System design from https://www.enjoyalgorithms.com/system-design-courses/
• OPPs from https://www.enjoyalgorithms.com/oops-course/
• DBMS from https://www.geeksforgeeks.org/dbms/introduction-of-dbms-database-management-system-set-1/
• SQL questions from LeetCode

Hope this article helps you with your preparation!!!