Submission #945655

#	Time	Username	Problem	Language	Result	Execution time	Memory
945655		vjudge1	Amusement Park (CEOI19_amusementpark)	C++17	0 / 100	1 ms	348 KiB

amusementpark

#include <bits/stdc++.h>
#define int long long
#define all(x) x.begin(),x.end()
#define ff first
#define ss second
#define pb push_back
using namespace std;
vector <int> g[20];
int cl[20];
bool ok=1;
void dfs(int v){
    cl[v]=1;
    for(auto to : g[v]){
        if(cl[to]==0)dfs(to);
        else if(cl[to]==1)ok=0;
    }
    cl[v]=2;
}
signed main(){
    int n,m;
    cin>>n>>m;
    vector <int> u(m),v(m);
    for(int i=0;i<m;i++){
        cin>>u[i]>>v[i];
    }
    vector <int> ord;
    int ans=0;
    for(int i=1;i<=n;i++)ord.pb(i);
    do{
        vector <int> val_ord(n+1);
        for(int i=1;i<=n;i++){
            cl[i]=0;
            g[i].clear();
        }
        ok=1;
        for(int i=0;i<ord.size();i++){
            val_ord[ord[i]]=i;
        }
        
        int cnt=0;
        for(int i=0;i<m;i++){
            int x=val_ord[u[i]];
            int y=val_ord[v[i]];
            if(x<y){
                cnt++;
                g[v[i]].pb(u[i]);
            }
            else g[u[i]].pb(v[i]);
        }
        for(int i=1;i<=n;i++){
            if(!cl[i])dfs(i);
        }
        if(ok){
            ans+=cnt;
        }
    }while(next_permutation(all(ord)));
    cout<<ans<<"\n";
}


/*
 3 3
 1 2
 2 3
 1 3
 1 2 3
*/

Compilation message (stderr)

amusementpark.cpp: In function 'int main()':
amusementpark.cpp:36:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |         for(int i=0;i<ord.size();i++){
      |                     ~^~~~~~~~~~~

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