小G有一个大树 题目链接求树的重心 #include <bits/stdc++.h> using namespace std; typedef long long ll; typedef pair<int, int> PII; typedef pair<ll, ll> PLL; typedef unsigned long long ull; #define lsiz(x) int(x.size()) #define lch rt<<1 #define rch rt<<1|1 const ll Linf = 0x7f7f7f7f7f7f...