Why I can't get an answer for the Ship Puzzle with Prolog?
问题 I need to solve the Ship Puzzle problem with using Prolog. Here are the facts. There are 5 ships. The Greek ship leaves at six and carries coffee. The Ship in the middle has a black chimney. The English ship leaves at nine. The French ship with blue chimney is to the left of a ship that carries coffee. To the right of the ship carrying cocoa is a ship going to Marseille. The Brazilian ship is heading for Manila. Next to the ship carrying rice is a ship with a green chimney. A ship going to