设计一个交通咨询系统，能让旅客咨询从任一个城市顶点到另一个城市顶点之间的最短路径（里程）或最低花费或最短时间等问题。对于不同咨询要求，可输入城市间的路程或所需时间或所需费用。-Design a traffic advisory system, can let passengers from a city of consulting the vertices to another city between vertices of the shortest path (mileage) or the minimum cost or the shortest time. For different consultation request, can enter the journey between the cities or needed time or the required fee.