设计、实现一个全国大城市间的交通咨询程序，为旅客提供三种最优决策方案：（1）时间最短（2）费用最小（3）中转次数最少。-Design, implementation of a national inter-city traffic advisory procedures, provide passengers with three optimal decision-making program: (1) the shortest time (2) the cost of the smallest