How I Got the Interview Opportunity? 🎯

This was an On-Campus opportunity provided by my College — PICT (Pune Institute of Computer Technology), Pune.
PhonePe is one of the top companies visiting our Campus and is famous for asking good-level DSA questions.

It was my Dream Company from First Year itself as all the top Coders from our College used to get placed in PhonePe. So I was excited for the Interview Process.

They were the first company visiting for our batch 2022, around the last week of July 2021.
After we registered for PhonePe, we got the link to Online Test, which was the first step of the process.

🖥️ Online Assessment Round

This round was conducted on PhonePe’s DoSelect Platform, which is similar to any other DSA Test Environment.
The duration of the test was 2 hours. There were 4 Coding Questions with Medium-Hard difficulty level.

Problems Asked:

1. Count ways to exit matrix [N][M] (4 adjacent directions movements) from given (Sx, Sy) starting point in at most K steps.
   → Solvable in O(N * M * K) using DP

2. You can increment any A[i] by 1 (at most K times), find the maximum frequency of any A[i] possible.
   → Available on LeetCode. Solvable in O(N log N)
   → Approach: Sort Array. Fix L, find best R using binary search (prefix sums required).

3. Game Theory Problem: Given A and C, start with value A! (A factorial). Each player removes B (B ≤ A!) and B should have at most C distinct prime factors.

   • A, C ≤ 10^6
   • Answer: Count unique factors of A! If it is ≤ C, first wins else second wins

4. A Hard problem on Tree (not understandable, and no one solved it).

The CutOff for this round was 200 out of 400 (100 points per question, partials accepted).
Only 9 students (including me) from the whole college who appeared for the test were selected for the next Interview Rounds.

📩 I got the mail the next day that I had cleared the OA and received the link for the First Interview Round, which was scheduled for the next day.

🔹 First Technical Interview Round (1 Hour Long)

📍 Platform: Google Meet & CodeSignal
📍 Difficulty Level: Easy-Medium
📍 Interviewer: SDE-1 at PhonePe (1.5 years of experience)

The interview began with a general introduction of mine.
He then asked about my Hackerearth Internship and how to set problems, generate test cases, and automate them.

DSA Questions Asked:

1. Find the missing number in a sorted array of size N-1 (consisting of all numbers from 1 to N).

   • My Solution: Expected O(log N) → Binary Search ✅ (Very Easy Problem)

2. Pick K elements from either the start or end of the array such that their sum is maximum.

   • My Solution: Iterate on count of prefix elements from 0 to K and take suffix elements accordingly.
   • Expected Time Complexity: O(N) ✅ (Easy Problem)

3. Query Problem: Given an array of integers, answer queries of type L R D — Count numbers from L to R where the number of digits in that number ≥ D.

   • My Solution: O(N log N) precomputation & O(1) query. Used 2D prefix sum array. ✅ (Medium Problem)

📞 Result: I got a call confirming my selection for the next round (with 5 others).

🔹 Second Technical Interview Round (1 Hour Long)

📍 Platform: Same as Round 1
📍 Interviewer: 3+ years of experience at PhonePe

After a short introduction, the interviewer asked the following Coding Questions:

1. Covid Spread in a Binary Tree

   • Given a Binary Tree where nodes are people, the deepest leaf node gets Covid+ first, and the virus spreads to neighboring nodes in 1 sec. Find total time to spread in the whole tree.
   • My Solution: The answer is the Diameter of the Binary Tree (one of the farthest nodes is the first Covid+ node).
   • Time Complexity: O(N) ✅

2. Evaluate a mathematical expression containing brackets, operators, and numbers.

   • My Solution: Used Two Stacks (one for operands & brackets, one for numbers).
   • Time Complexity: O(N) ✅

📞 Result: After some time, I received a call that I had qualified for the Final Round with 2 others! 🎉

🔹 Third HR Interview Round (1 Hour Long)

📍 Platform: Google Meet
📍 Interviewer: Head of a Department at PhonePe

This was a non-technical round with resume discussion and some general questions.

Questions Asked:

• Internships Discussion:

  • Hackerearth: What topics do you usually set problems on?
  • Vicevio (Flutter Internship): How did you improve the architecture & contributions?

• Have you developed any Android App that solved a daily life problem?

📞 Final Question: Why do you think you are the best fit for PhonePe?

🌟 This was my best round! The interviewer was very friendly, and I felt confident.

🎉 Result: I GOT SELECTED! 🎉

After 2-3 hours, I got a call from PhonePe saying that I had been selected!
This was a dream come true for me as I had been aiming for PhonePe since my first year.
Getting placed on the first day of the Placement Season made it even more special.

🔥 Some Tips:

• OA Round was Hard 💻 but Interview Rounds were Easy-Medium (mostly Leetcode-style questions).
• Keep interacting with the Interviewer instead of staying silent while thinking.
• Explain easy problems well—most candidates will solve them, but good explanation can make a difference.
• If you don’t know an answer, admit it early rather than diving in blindly.