B - Catch That Cow(BFS)
简单、BFS,注意的是因为有-1,所以状态会有返回并反复将相同的状态装入队列的情况,为了增加效率,防止内存超出,应该标记每次所经历过的状态,防止对同一个状态的多次访问。DescriptionFarmer John has been informed of the location of a fugitive cow and wants to catch her imme