说明：  使用遗传算法求解TSP问题。假设有一个旅行商人要拜访n个城市，他必须选择所要走的路径，路径的限制是每个城市只能拜访一次，而且最后要回到原来出发的城市。
(Genetic algorithm is used to solve TSP problem. Suppose there is a traveler who wants to visit n cities, he must choose the path he wants to take. The limit of the path is that each city can only visit once, and finally return to the original city.)