#include <bits/stdc++.h>
#include "traffic.h"
#define pb push_back
#define ll long long
using namespace std;
vector<vector<int>> adj;
vector<ll> sum;
ll min_traffic, centre, total = 0;
int dfs(int u, int p, int* P) {
sum[u] = P[u];
ll traffic = 0;
for (int v: adj[u]) {
if (v == p) continue;
sum[u] += dfs(v, u, P);
traffic = max(traffic, sum[v]);
}
traffic = max(traffic, total-sum[u]);
if (traffic < min_traffic) {
min_traffic = traffic;
centre = u;
}
return sum[u];
}
int LocateCentre(int N, int* P, int* S, int* D) {
adj = vector<vector<int>>(N);
sum = vector<ll>(N);
for (int i = 0; i < N-1; ++i) {
adj[S[i]].pb(D[i]);
adj[D[i]].pb(S[i]);
}
for (int i = 0; i < N; ++i) total += P[i];
min_traffic = 1e18, centre = -1;
dfs(0, 0, P);
return centre;
}
