#include <traffic.h>
#include <vector>
#define MAXN 1000000
using namespace std;
int pop[MAXN];
vector<int> vals[MAXN];// amt congestion for each path coming out
vector<int> adj[MAXN];
int total = 0; // total people everywhere
int ans = 2000001;
int dfs(int x, int y) {//y is back edge
int amt = pop[x];
for (int e : adj[x]) {
if (e == y) continue;
int edge = dfs(e, x);
vals[x].push_back(edge);
amt += edge;
}
return amt;
}
int LocateCentre(int N, int P[], int S[], int D[]) {
for (int i = 0; i < N - 1; i++) {
total += P[i];
pop[i] = P[i];
adj[S[i]].push_back(D[i]);
adj[D[i]].push_back(S[i]);
}
total += P[N - 1];
pop[N-1] = P[N - 1];
dfs(0, -1);
for (int i = 0; i < N; i++) {
int mx = 0;
int amt = 0;
for (int val : vals[i]) {
mx = max(mx, val);
amt += val;
}
mx = max(mx, total - amt - pop[i]);
ans = min(ans, mx);
}
return ans;
}
