Three rounds, all technical.

First round was with the Hiring Manager. He asked me about the project and a coding question: the rainwater trapping problem. He was expecting a stack-based solution. I implemented it, but my answer was wrong, so he was helping me, but we could not find the mistake. Eventually, he agreed to let it be.

Second round was with a Senior Engineer or Staff Engineer. He asked about microservices, how they communicate with each other, high availability architecture, quorum-based leader decisions, and how message queues work. There was one coding question: find the first non-repeating character in a string.

Third round was also similar. He asked me about microservices and their details, and one coding question which I could not solve within the time limit: find the first missing positive integer in an array in O(N) time and O(1) space.

1. Rainwater trapping question.

2. Find the first non-repeating character in a string.

3. Find the first missing positive integer in an array in O(N) time and O(1) space.

4. Microservices and their architecture.

   • How do they communicate?
   • How does asynchronous communication work?
   • Design-based questions, such as how to ensure high availability of the system.