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。

-From the entrance to the exit of a maze to find an available path through. With a two-dimensional array MG (1: M, 1: N) simulated maze, an array element of 0 indicates that the location can be passed as an array element that can not access the location. MG (1,1) and MG (M, N) respectively, the maze entrance and exit.