说明：  我收藏的python下的迷宫路径搜索，用的是回溯法。为方便起见，程序没有记录行走路径，只输出路径所经历过的方块。
(I collected the maze under the python search path, using a retroactive law. For the sake of convenience, the program did not record walking path, only the output path of the box experiences.)