中文说明：关于路径深度搜索方法的代码及课件。ppt将原理讲得很是深入浅出，对代码实现有一定指导意义。然后自己根据项目进行了修改。
English Description：
About the path depth search method code and courseware. Ppt explains the principle in simple terms, which has a certain guiding significance for code implementation. Then I modified it according to the project.