Two on-campus interviews were conducted on October 8, 2019, and October 9, 2019. I was rejected on October 16, 2019.

After the first on-campus interview on October 8, I was directly scheduled for another interview on October 9. At the end of the interview on October 9, they told me only that I would receive an email from HR in a few days.

Given an N*M grid, each grid cell can either contain a ship or be empty. Implement a function that calculates the number of ships inside a given rectangle. You have another given function that can check whether there is any ship inside a given rectangle.