Submission #123547

#	Time	Username	Problem	Language	Result	Execution time	Memory
123547		Noam527	007 (CEOI14_007)	C++17	0 / 100	302 ms	22268 KiB

007

#include <bits/stdc++.h>
#define finish(x) return cout << x << endl, 0
typedef long long ll;
typedef long double ldb;
const int md = 1e9 + 7;
const ll inf = 1e18;
const int OO = 1;
const int OOO = 1;
using namespace std;

int n, m;
int st7, stn, a, b;
vector<vector<int>> g;
vector<int> d;

void bfs(int st) {
	for (auto &i : d) i = -1;
	d[st] = 0;
	queue<int> q;
	q.push(st);
	while (q.size()) {
		int x = q.front();
		q.pop();
		for (const auto &i : g[x])
			if (d[i] == -1) {
				d[i] = 1 + d[x];
				q.push(i);
			}
	}
}

int main() {
	ios::sync_with_stdio(0), cin.tie(0);
	cin >> n >> m >> st7 >> stn >> a >> b;
	--st7, --stn, --a, --b;
	g.resize(n);
	d.resize(n);
	for (int i = 0, u, v; i < m; i++) {
		cin >> u >> v;
		--u, --v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	bfs(st7);
	int D7[2] = { d[a], d[b] };
	bfs(stn);
	int Dn[2] = { d[a], d[b] };
	int ans = min(Dn[0] - D7[0], Dn[1] - D7[1]);
	cout << max(ans, -1) << '\n';
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 70