Solution -「LOJ 3310」丁香之路
首先有两个前置技巧:1) 两点间的最短距离就是直接连接两点的边的长度;2) 遍历一个子图的最小花费是最小生成树的边权之和乘二。原问题让我们找出一条最短且必经过钦定边的 $( s, i )$ 路径...
In mathematics you don't understand things, you just get used to them.
In mathematics you don't understand things, you just get used to them.