#include <bits/stdc++.h>
#include "traffic.h"
using namespace std;
#define FAST ios_base::sync_with_stdio(false); cin.tie(NULL)
vector<int> adj[1000000];
int tot_peo[1000000], ans[1000000], peo[1000000];
// refer kartik arora's dp on trees youtube videos
// idea is taken from his tree distance ii video
void dfs1(int u, int p = -1) {
tot_peo[u] = peo[u];
for (int v : adj[u])
if (v != p) {
dfs1(v, u);
tot_peo[u] += tot_peo[v];
}
}
void dfs2(int u, int p = -1) {
ans[u] = 0;
for (int v : adj[u])
if (v != p)
ans[u] = max(ans[u], tot_peo[v]);
if (p != -1)
ans[u] = max(ans[u], tot_peo[0] - tot_peo[u]);
for (int v : adj[u])
if (v != p)
dfs2(v, u);
}
int LocateCentre(int N, int P[], int S[], int D[]) {
for (int i = 0; i < N - 1; i++) {
adj[S[i]].push_back(D[i]);
adj[D[i]].push_back(S[i]);
}
for (int i = 0; i < N; i++)
peo[i] = P[i];
dfs1(0);
dfs2(0);
int mn = 2e9;
for (int i = 0; i < N; i++)
mn = min(mn, ans[i]);
return mn;
}
