//神题目(题目一开始就理解错了)... 题目描述 Why did the cow cross the road? Well, one reason is that Farmer John's farm simply has a lot of roads, making it impossible for his cows to travel around without crossing many of them. 奶牛们为什么要穿马路?一个原因只是因为FJ的牧场的路实在是太多了,使得奶牛们每…
[洛谷P2921] [USACO08DEC]在农场万圣节Trick or Treat on the Farm 题目描述 每年,在威斯康星州,奶牛们都会穿上衣服,收集农夫约翰在N(1<=N<=100,000)个牛棚隔间中留下的糖果,以此来庆祝美国秋天的万圣节. 由于牛棚不太大,FJ通过指定奶牛必须遵循的穿越路线来确保奶牛的乐趣.为了实现这个让奶牛在牛棚里来回穿梭的方案,FJ在第i号隔间上张贴了一个"下一个隔间"Next_i(1<=Next_i<=N),告诉奶牛要去…