I applied through a job portal.

The first round was problem-solving, featuring a medium-level, string-based problem. I passed that round.

The second round was supposed to be a design question, but the problem presented was not a design challenge. Additionally, the interviewer became non-responsive at times. I managed to solve the question, but was ultimately rejected without clear reason.

I contacted HR for detailed feedback, but received no response.

Write a JSON comparator.

Write a method to handle parallel order processing where an order contains a list of items with quantities. You can assume inventory is already populated and present in in-memory storage.