要确定从s到V中没一个其他 顶点的距离，这里从顶点s到x的距离定义为从s到x的最短路径问题。这个问题 可以用Dijkstra算法解决-To determine V from s to no one other vertex in the distance, where x from vertex s to the distance from s to x is defined as the shortest path problem. This problem can be reso