Submission #339152

#	Time	Username	Problem	Language	Result	Execution time	Memory
339152		Ta180m	Traffic (IOI10_traffic)	C++17	100 / 100	1333 ms	149096 KiB

traffic

#include "traffic.h"
#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
using ll = long long;
using ii = pair<int, int>;
constexpr int MX = 1e6+5;


int sum, sz[MX];
ii ans(2e9, 0);
vector<int> G[MX];

void dfs(int u, int p) {
	for (int v : G[u]) if (v != p)
		dfs(v, u), sz[u] += sz[v];
}

void solve(int u, int p, int P[]) {
	int up = sum-P[u], mx = 0;
	for (int v : G[u]) if (v != p)
		up -= sz[v], mx = max(sz[v], mx);
	mx = max(up, mx);
	if (mx < ans.f) ans = ii(mx, u);

	for (int v : G[u]) if (v != p)
		solve(v, u, P);
}

int LocateCentre(int N, int P[], int S[], int D[]) {
	for (int i = 0; i < N-1; ++i)
		G[S[i]].push_back(D[i]),
		G[D[i]].push_back(S[i]);
	
	for (int i = 0; i < N; ++i)
		sum += P[i], sz[i] = P[i];
	dfs(0, -1);
	solve(0, -1, P);
	return ans.s;
}

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 25 / 25
• Subtask 4: 25 / 25