Submission #391853

#	Time	Username	Problem	Language	Result	Execution time	Memory
391853		wiwiho	007 (CEOI14_007)	C++14	30 / 100	275 ms	16992 KiB

007

#include <bits/stdc++.h>

#define eb emplace_back
#define mp make_pair
#define F first
#define S second
#define printv(a, b) {\
    for(auto pv : a) b << pv << " ";\
    b << "\n";\
}

using namespace std;

using pii = pair<int, int>;

ostream& operator<<(ostream& o, pii p){
    return o << '(' << p.F << ',' << p.S << ')';
}

int n, m;
vector<vector<int>> g;

vector<int> getdis(int s){
    vector<int> dis(n + 1, -1);
    dis[s] = 0;
    queue<int> q;
    q.push(s);
    while(!q.empty()){
        int now = q.front();
        q.pop();
        for(int i : g[now]){
            if(dis[i] != -1) continue;
            dis[i] = dis[now] + 1;
            q.push(i);
        }
    }
    return dis;
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    cin >> n >> m;

    int s, d, a, b;
    cin >> s >> d >> a >> b;

    g.resize(n + 1);
    for(int i = 0; i < m; i++){
        int u, v;
        cin >> u >> v;
        g[u].eb(v);
        g[v].eb(u);
    }

    vector<int> ds = getdis(s);
    vector<int> dd = getdis(d);
    vector<int> da = getdis(a);
    vector<int> db = getdis(b);

    int tmp = min(dd[a], dd[b]);
    int ans = ds[a];
    for(int i = 1; i <= n; i++){
        if(da[i] <= 1 && db[i] <= 1){
            ans = min(ds[i], ans);
        }
    }
    ans = tmp - 1 - ans;
    ans = max(ans, -1);
    cout << ans << "\n";

    return 0;
}

• Subtask 1: 9 / 30
• Subtask 2: 21 / 70