猎人要带一条狼、一只羊和一棵大白菜过河。船太小，一次只能带一样。但猎人不在场的情况下，狼要吃羊，羊要吃白菜。请设计一个C++程序为猎人指出一个安全的渡河放案。 资源中有c++源程序和文档说明-Hunters to take a wolf, a sheep and a cabbage across the river. Ship is too small, one can only bring the same. However, the presence of hunters, the wolf