In this round, a detailed discussion on the different projects that I had done took place. He asked me a lot of behavioral questions as well throughout the discussion.

After that, I was asked some basic OS questions, like how Multithreading differs from Multiprocessing, and I had to distinguish between them using examples. I was asked about different abstraction levels in a Database Management System.

I was asked about the working of Hashmaps: Where are they used? When shouldn’t they be used?

Why would I be using NoSQL databases over SQL databases, plus my particular inclination towards MongoDB?

Then we started discussing the work culture of the company and the difference it has been creating in the recent past.

Problem

You are given integers n and k, where n is the number of points on the x-axis and k is the number of available colors of a butterfly.

You want to place these butterflies on the x-axis next to each other such that no butterfly of the same color is sitting adjacent. Also, there is another integer p which means butterflies of color p are allowed to sit adjacent to each other.

Find the number of such possible arrangements mod 10^9 + 7.