Submission #2247975

---

Source Code Expand

#include<bits/stdc++.h>
using namespace std;
int n,m,ans;
bool used[9],d[9][9];
 
void dfs(int p,int c){
  if(c==n)ans++;
  used[p]=1;
  for(int i=1;i<=n;i++)
    if(!used[i]&&d[p][i])dfs(i,c+1);
  used[p]=0;
}
 
int main(){
  cin>>n>>m;
  for(int i=0,a,b;i<m;i++){
    cin>>a>>b;
    d[a][b]=d[b][a]=1;
  }
  dfs(1,1);
  cout<<ans<<endl;
  return 0;
}

Submission Info

Judge Result