SDE-3 at J.P. Morgan

How it went

What they would tell you

How to prepare

Their background

Round by round

1. 1

   Online Assessment60 min

   The online assessment consisted of two medium-level questions to be solved within 60 minutes. Q1: Given a list of arrival and departure times for trains at a station, determine the minimum number of platforms needed so no train has to wait. Q2: Given a string, count all valid substrings where no two adjacent characters are the same, and the substring length is within a specific range (for example minLen = 2, maxLen = 4) Both problems required careful thought about edge cases,I solved both in time, with all test cases passing.

   • Minimum number of platforms required for a railway
2. 2

   Technical Round 160 min

   This round incude two sections,a PR review section, I was presented with a pull request and its description. I had to identify below key points

   • Design principles: Is the code modular? Are responsibilities clear?
   • Security: Are there SQL injection risks? What about middleware attacks?
   • Logging: Are important events being logged? Are logs clear and useful?
   • Clean code: Is the code style consistent? Is it easy to read and maintain?
   • Concurrency: Are there race conditions or deadlock risks?
   • Error handling: Are exceptions caught and logged appropriately? I talked through each point, suggesting improvements and asking clarifying questions. DSA section involved a matrix problem where I had to find the median of the entire matrix, given a 2D matrix where each row is individually sorted in ascending order.
   • Matrix Median
3. 3

   System Design60 min

   The next round was system design, where I was asked to design a real-time ride-sharing platform. The system had to match riders with nearby drivers efficiently while handling dynamic location updates and surge pricing. I started by defining functional and non-functional requirements, followed by a high-level design diagram, database tables and columns for users, drivers, rides, and payments, and APIs for requesting rides, updating locations, and calculating fares.

4. 4

   Final Behavioral Round60 min

   Question were like how I handle conflicts within a team when there is a disagreement on a technical solution, how I prioritize tasks when multiple high-priority projects are assigned simultaneously and how I approach debugging critical production issues under tight deadlines.

What came up