说明：  C++开发的。农夫过河。一个农夫带着一只狼，一只羊和一些菜过河。河边只有一条一船，由 于船太小，只能装下农夫和他的一样东西。在无人看管的情况下，狼要吃羊，羊要吃菜，请问农夫如何才能使三样东西平安过河。
(C development. Farmers across the river. A farmer with a wolf, a goat and some vegetables across the river. Only a river boat, the boat is too small to install under the farmer and his thing. Unattended circumstances, the wolf to Qiyang, the sheep to the meal, ask the farmers how to make three things safely across the river.)