题目
Figure 3 models a network of cycle lanes that must be inspected. The number on each arc represents the length, in km, of the corresponding cycle lane. Lance needs to cycle along each lane at least once and wishes to minimise the length of his inspection route.
[The total weight of the network is 166]
He must start and finish at A.
(a) Use an appropriate algorithm to find the length of the route. State the cycle lanes that Lance will need to traverse twice. You should make your method and working clear.
(b) State the number of times that vertex C appears in Lance’s route.
It is now decided that the inspection route may finish at any vertex. Lance will still start at A and must cycle along each lane at least once.
(c) Determine the finishing point so that the length of the route is minimised. You must give reasons for your answer and state the length of this new minimum route.
题目中文翻译
图 3 模拟了一个需要检查的自行车道网络。每条弧上的数字表示对应自行车道的长度（单位：km）。Lance 需要每条车道至少经过一次，并希望最小化检查路线的长度。
[网络总权重为 166]
他必须从 A 出发并回到 A。
(a) 使用适当的算法找到路线的长度。写出 Lance 需要经过两次的自行车道。应清楚说明方法和计算过程。
(b) 写出顶点 C 在 Lance 路线中出现的次数。
现在决定检查路线可以在任何顶点结束。Lance 仍然从 A 开始，必须每条车道至少经过一次。
(c) 确定结束点以使路线长度最短。必须给出理由并写出此新最小路线的长度。