说明：  带权图的最短路径问题,主要介绍单源最短路径算法，最短路径问题的提法很多，其它的最短路径问题均可用单源最短路径算法予以解决
(Weighted graph shortest path problem, mainly introduce single-source shortest path algorithm, the shortest path problem formulation of a lot of other shortest path problem can be used single-source shortest path algorithm to be addressed)