目前网络上电子地图的使用很普遍。利用电子地图可以很方便地确定从一个地点到另一个地点的路径。特别地，可确定在城市中的公交换乘路线。



电子地图可以看成是一个图，而公交线路图可看成是带权有向图G =(V,E)，其中每条边的权是非负实数。







你的任务：对给定的一个（无向）图G，及G中的两点s、t，计算从顶点s到顶点t的最短距离和最少路段数。-On the network, the use of electronic maps is common. Electronic map can easily determine the path from one location to another. In particular, you can determine the bus transfer routes in the city. Electronic map can be seen as a map, bus route map can be viewed as a weighted directed graph G = (V, E), in which each side the right to non-negative real numbers. Your mission: on a given one (undirected) graph G, and G of the two points s and t, calculated from the vertex s to the vertex t shortest distance and minimum road number.