中文说明：用 Floyd 算法求任意两点间的最短路径及最短路长. D0 是图的邻接矩阵-Floyd algorithm used for any shortest path between two points and the most long-short-circuit. D0 is the graph adjacency matrix
English Description：
Floyd algorithm used for any shortest path between two points and the most long-short-circuit. D0 is the graph adjacency matrix