Consider the following problem Given a standard 8x8 chessboard, put on it as few bishops as possible in such a way that every square is under attack

Consider the following problem

Given a standard 8x8 chessboard, put on it as few bishops as possible in such a way that every square is under attack by one of the bishops

Represent this problem as an algorithmic problem. What is this algorithmic problem? Is it possible to solve it in a polynomial time? What algorithm would you use to find a solution? Explain you answers.