Submission #446204

#	Time	Username	Problem	Language	Result	Execution time	Memory
446204		Haruto810198	Amusement Park (CEOI19_amusementpark)	C++17	7 / 100	1 ms	232 KiB

amusementpark

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define double long double

#define FOR(i,l,r,d) for(int i=(l);i<=(r);i+=(d))
#define szof(x) ((int)(x).size())

#define vi vector<int>
#define pii pair<int,int>

#define F first
#define S second

#define pb push_back
#define eb emplace_back
#define mkp make_pair

const int INF = 2147483647;
const int LNF = INF*INF;
const int MOD = 1000000007;
const int mod = 998244353;
const double eps = 1e-12;

//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")

int n, m;
vector<pii> edges;
int res;

void check(int mask){

    bool edge[20][20];
    int indeg[20];
    int val = 0;

    FOR(i, 1, n, 1){
        indeg[i] = 0;
        FOR(j, 1, n, 1){
            edge[i][j] = 0;
        }
    }

    FOR(i, 0, m-1, 1){
        if( (mask & (1<<i)) == 0 ){
            edge[ edges[i].F ][ edges[i].S ] = 1;
            indeg[ edges[i].S ] = 1;
        }
        else{
            edge[ edges[i].S ][ edges[i].F ] = 1;
            indeg[ edges[i].F ]++;
            val++;
        }
    }

    vi qu;
    int vis = 0;
    FOR(i, 1, n, 1){
        if(indeg[i] == 0){
            qu.pb(i);
            vis++;
        }
    }

    while( !qu.empty() ){

        int v = qu.back();
        qu.pop_back();

        FOR(i, 1, n, 1){
            if(edge[v][i] == 1){
                indeg[i]--;
                if(indeg[i] == 0){
                    qu.pb(i);
                    vis++;
                }
            }
        }

    }

    if(vis == n){
        res += val;
    }

}

signed main(){

    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    cin>>n>>m;

    edges.resize(m);
    FOR(i, 0, m-1, 1){
        cin>>edges[i].F>>edges[i].S;
    }

    res = 0;
    FOR(mask, 0, (1<<m)-1, 1){
        check(mask);
    }

    cout<<res<<'\n';

    return 0;

}

• Subtask 1: 7 / 7
• Subtask 2: 0 / 12
• Subtask 3: 0 / 23
• Subtask 4: 0 / 21
• Subtask 5: 0 / 37