城市间交通网问题

现有N座城市组成的公路交通网络，其中有的城市之间有直达公路（途中不经过其他城市），有的城市之间没有直达公路。我们作一些约定：城市间存在直达的公路路段上，往返的行车时间不一定相等（因为可能存在上下坡等因素，所以这个假设是合理的）。每条有方向的边上的二元组分别表示该方向上直线距离和车速。要求编程设计一个简单的交通路线查询系统，实现一些有关任一城市周边城市查询、任何两个地点的最短行车时间、最小中转次数查询等功能。-The issue of inter-city transport network composed of existing N cities road transport network, in which some cities have direct access to Highway (passing through other cities on his way), some cities do not have direct access to highways. We make some agreement: the existence of direct inter-city road sections, the round-trip travel time is not necessarily the same (because they may be the existence of factors such as downhill, so this assumption is reasonable). Has the direction of each edge of the dual group said that the direction of straight-line distance and speed. Programming a simple request of the transport routes of referral systems, to achieve some of the cities surrounding the city of any inquiries, any two points of the shortest travel time, minimum number of inquiries, such as transfer function.