Submission #3947935

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Source Code Expand

#include<iostream>
#include<string>
#include<vector>
#include<queue>
#include<stack>
#include<map>
#include<unordered_map>
#include<set>
#include<algorithm>
#include<functional>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cassert>
#include<ctime>
using namespace std;

#define mind(a,b) (a>b?b:a)
#define maxd(a,b) (a>b?a:b)
#define absd(x) (x<0?-(x):x)
#define pow2(x) ((x)*(x))
#define rep(i,n) for(int i=0; i<n; ++i)
#define repr(i,n) for(int i=n-1; i>=0; --i)
#define repl(i,s,n) for(int i=s; i<=n; ++i)
#define replr(i,s,n) for(int i=n; i>=s; --i)
#define repf(i,s,n,j) for(int i=s; i<=n; i+=j)
#define repe(e,obj) for(auto e : obj)

#define SP << " " <<
#define COL << " : " <<
#define COM << ", " <<
#define ARR << " -> " <<
#define PNT(STR) cout << STR << endl
#define POS(X,Y) "(" << X << ", " << Y << ")"
#define DEB(A) " (" << #A << ") " << A
#define DEBREP(i,n,val) for(int i=0; i<n; ++i) cout << val << " "; cout << endl
#define ALL(V) (V).begin(), (V).end()
#define INF 1000000007
#define INFLL 1000000000000000007LL
#define EPS 1e-9

typedef unsigned int uint;
typedef unsigned long ulong;
typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
#define P_TYPE int
typedef pair<P_TYPE, P_TYPE> P;
typedef pair<P, P_TYPE> PI;
typedef pair<P_TYPE, P> IP;
typedef pair<P, P> PP;
typedef priority_queue<P, vector<P>, greater<P> > pvqueue;

#define N 22
#define MOD 1000000007
#define N0 (1 << 21)

int n;
int a[N][N];

ll memo[N][N0];
ll dfs(int i, int state) {
  ll r = 0;
  if(i == n) return 1;
  if(memo[i][state] != -1) {
    return memo[i][state];
  }
  rep(j, n) {
    if(a[i][j] && ((state & (1 << j)) == 0)) {
      r = (r + dfs(i+1, state | (1 << j))) % MOD;
    }
  }
  return memo[i][state] = r;
}

int main() {
  cin >> n;
  rep(i, n) rep(j, n) cin >> a[i][j];
  rep(i, n) rep(j, 1<<n) memo[i][j] = -1;
  cout << dfs(0, 0) << endl;
  return 0;
}

Submission Info

Judge Result