题目
Figure 2 represents a network of roads connecting a group of villages. The number on each arc is the length, in km, of the corresponding road.
[The total length of the network is 338]
Bolin needs to inspect the network in Figure 2. He must travel along each road at least once, minimising the length of his route.
Bolin’s route must start at A and finish at J.
(a) Determine the length of Bolin’s route. You must make your method clear and state the roads which need to be repeated.
A new road is constructed from F to J which has length 18 km. Bolin must inspect the changed network, starting at A and finishing at J. He must travel along each road at least once, minimising the length of his route.
(b) Determine the change to the length of Bolin’s route.
题目中文翻译
图 2 表示连接一群村庄的道路网络。每条弧上的数字是对应道路的长度（单位：km）。
[网络总长度为 338]
Bolin 需要检查图 2 中的网络。他必须每条道路至少经过一次，同时最小化路线长度。
Bolin 的路线必须从 A 出发，到 J 结束。
(a) 确定 Bolin 路线的长度。必须清楚说明方法并指出需要重复经过的道路。
现修建一条从 F 到 J 的新道路，长度为 18 km。Bolin 必须检查变化后的网络，从 A 出发到 J 结束。他必须每条道路至少经过一次，同时最小化路线长度。
(b) 确定 Bolin 路线长度的变化。