解决商人渡河问题。该问题为：有三个商人，三个强盗，和一条船（船每次只可以载小于等于两个人）他们同在河的一边，想渡过河去，但是必须保证在河的任何一边必须保证商人的数目大于等于强盗的数目，并要满足渡河次数尽可能的少，应该怎么过这条河呢？ -To solve business problems crossing. The problem is: There are three businessmen, three robbers, and a boat (each boat can only c