视频链接：E65树形DPP3237[HNOI2014]米特运输_哔哩哔哩_bilibili  P3237[HNOI2014]米特运输-洛谷|计算机科学教育新生态(luogu.com.cn)//树形DPO(n)#include<bits/stdc++.h>#defineintlonglongusingnamespacestd;constintN=500005,mod=1e9+7;