Submission #101535

#	Time	Username	Problem	Language	Result	Execution time	Memory
101535		lyc	007 (CEOI14_007)	C++14	0 / 100	380 ms	15864 KiB

007

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
#define fi first
#define sc second
#define SZ(x) (int)(x).size()
#define ALL(x) (x).begin(), (x).end()

int main() {
    //freopen("in.txt", "r", stdin);
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m; cin >> n >> m;
    vector<int> al[n+1];
    int s, d, a, b; cin >> s >> d >> a >> b;
    for (int i = 0; i < m; ++i) {
        int u, v; cin >> u >> v;
        al[u].push_back(v);
        al[v].push_back(u);
    }

    queue<int> q;
    int dist1[n+1], dist2[n+1];
    memset(dist1, -1, sizeof dist1);
    memset(dist2, -1, sizeof dist2);
    q.push(a); dist1[a] = 0;
    while (!q.empty()) {
        int u = q.front(); q.pop();
        for (auto v : al[u]) {
            if (dist1[v] == -1) {
                dist1[v] = dist1[u]+1;
                q.push(v);
            }
        }
    }

    q.push(b); dist2[b] = 0;
    while (!q.empty()) {
        int u = q.front(); q.pop();
        for (auto v : al[u]) {
            if (dist2[v] == -1) {
                dist2[v] = dist2[u]+1;
                q.push(v);
            }
        }
    }

    //cout << dist1[s] << " " << dist2[s] << endl;
    //cout << dist1[d] << " " << dist2[d] << endl;
    cout << max(-1, min(dist2[d] - dist2[s], dist1[d] - dist1[s])) << '\n';
}

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