从一个迷宫的入口到出口找出一条可通路经。用一个二维数组MG(1：M，1：N)模拟迷宫，数组元素为0表示该位置可以通过，数组元素为1表示该位置不可以通行。MG(1，1)和MG(M，N)分别为迷宫的入口和出口。若存在一条可通路经，输出YES，否则输出NO-From the entrance to the exit of a maze to find an available path through. Two-dimensional arrays with a MG (1: M, 1: N) simulated maze, the array elements of 0 indicates that the location can be passed, the array elements is 1 indicates that the location can not access. MG (1,1) and MG (M, N) respectively, the maze entrance and exit. If there is an available path through the output YES, otherwise output NO