Submission #790716

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Source Code Expand

#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
using namespace std;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll; typedef map<int, int> mii;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int main(void){
  long long int n,m;
  cin >> n>>m;
  ll ans;
  int x[m];
  int y[m];
  std::vector<int> data;
  for (int i = 0; i < m; i++){
    cin >> x[i] >> y[i];
  }
  ll count = 0;
   for(int i=0; i<n; ++i){
    data.push_back(i+1);
  }
   do{
     int flag = 1;
     rep (i,m) {
       int a,b;
       rep(j,n) {
	 if(data[j]==x[i]){
	   a = j;
	   break;
	 }
       }
       rep(j,n) {
	 if(data[j]==y[i]){
	   b = j;
	   break;
	 }
       }
       if (a < b) {
	 flag = 0;
	 break;
       }
     }
     if(flag) {
       count++;
     }
  }while(next_permutation(data.begin(), data.end()));
    cout << count << endl;
  return 0;
}

Submission Info

Judge Result