[[Image:TSP Deutschland 3.png|thumb|200px|An optimal traveling salesperson tour through [[Germany]]’s 15 largest cities. It is the shortest among 43,589,145,600<ref>Take one city, and take all possible orders of the other 14 cities. Then divide by two because it does not matter in which direction in time they come after each other: 14!/2 = 43,589,145,600.</ref> possible tours visiting each city exactly once.]] | [[Image:TSP Deutschland 3.png|thumb|200px|An optimal traveling salesperson tour through [[Germany]]’s 15 largest cities. It is the shortest among 43,589,145,600<ref>Take one city, and take all possible orders of the other 14 cities. Then divide by two because it does not matter in which direction in time they come after each other: 14!/2 = 43,589,145,600.</ref> possible tours visiting each city exactly once.]] |