O-Matching.cpp

//Radhe Radhe
#include<bits/stdc++.h>
//#include<boost/multiprecision/cpp_int.hpp>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//using namespace boost::multiprecision;
//#include<boost/math/common_factor.hpp>
#include <ext/numeric>
using namespace __gnu_cxx;
using namespace std;
#define int long long
#define endl "\n"
#define F first
#define S second
#define pb push_back
#define mp make_pair
#define array(a,n) int a[n]; for(int i=0;i<n;i++) cin>>a[i];
#define loop(i,a,b,x) for(int i=a;i<b;i+=x)
const int MOD = 1000000007;

int32_t main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
#endif

    int t = 1;
    //cin >> t;
    while (t--) {
        int n, a[25][25] = {}, dp[1 << 22] = {};
        cin >> n;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                cin >> a[i][j];
            }
        }
        dp[0] = 1;
        for (int i = 0; i < (1 << n); i++) {
            int cnt = __builtin_popcount(i);
            for (int j = 0; j < n; j++) {
                if ((i & (1 << j)) && a[cnt - 1][j]) {
                    (dp[i] += dp[i ^ (1 << j)]) %= MOD;
                }
            }
        }
        cout << dp[(1 << n) - 1] << endl;
    }
    return 0;

}