Submission #2162049

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Source Code Expand

#include <bits/stdc++.h>
#define ADD(a, b) a = (a + ll(b)) % mod
#define MUL(a, b) a = (a * ll(b)) % mod
#define MAX(a, b) a = max(a, b)
#define MIN(a, b) a = min(a, b)
#define rep(i, a, b) for(int i = int(a); i < int(b); i++)
#define rer(i, a, b) for(int i = int(a) - 1; i >= int(b); i--)
#define all(a) (a).begin(), (a).end()
#define sz(v) (int)(v).size()
#define pb push_back
#define sec second
#define fst first
#define debug(fmt, ...) Debug(__LINE__, ":", fmt, ##__VA_ARGS__)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<int, pi> ppi;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> mat;
typedef complex<double> comp;
void Debug() {cout << '\n'; }
template<class FIRST, class... REST>void Debug(FIRST arg, REST... rest){
	cout<<arg<<" ";Debug(rest...);}
template<class T>ostream& operator<<(ostream& out,const vector<T>& v) {
	out<<"[";if(!v.empty()){rep(i,0,sz(v)-1)out<<v[i]<<", ";out<<v.back();}out<<"]";return out;}
template<class S, class T>ostream& operator<<(ostream& out,const pair<S, T>& v){
	out<<"("<<v.first<<", "<<v.second<<")";return out;}
const int MAX_N = 200010;
const int MAX_V = 100010;
const double eps = 1e-6;
const ll mod = 1000000007;
const int inf = 1 << 29;
const ll linf = 1LL << 60;
const double PI = 3.14159265358979323846;
///////////////////////////////////////////////////////////////////////////////////////////////////

int N, M;
int G[15][15];

int to[15][(1 << 15)];
ll dp[(1 << 15)];
ll pow2[1000];

void solve() {
	cin >> N >> M;
	rep(i, 0, M) {
		int a, b; cin >> a >> b; a--; b--;
		G[a][b] = 1;
	}

	pow2[0] = 1;
	rep(i, 0, 500) pow2[i + 1] = pow2[i] * 2 % mod;

	rep(i, 0, N) {
		rep(bit, 0, (1 << N)) {
			if((bit & (1 << i))) continue;
			int tmp = 0;
			rep(j, 0, N) {
				if(!(bit & (1 << j))) continue;
				tmp += G[i][j];
			}
			to[i][bit] = tmp;
		}
	}
	dp[0] = 1;
	rep(q, 0, (1 << N)) {
		for(int bit = q; bit; bit = (bit - 1) & q) {
			if((bit & (1 << 0)) && (bit & (1 << 1))) continue;
			int pbt = bit ^ q;
			int rbt = (1 << N) - 1 - q;
			ll mul = 1;
			ll cnt = 0;
			rep(i ,0, N) {
				if(!(rbt & (1 << i))) continue;
				MUL(mul, pow2[to[i][bit]] - 1);
			}
			rep(i, 0, N) {
				if(!(pbt & (1 << i))) continue;
				ADD(cnt, to[i][bit]);
			}
			// debug(bitset<3>(q), bitset<3>(pbt), bitset<3>(bit), bitset<3>(rbt), dp[pbt], mul, cnt);
			ADD(dp[q], dp[pbt] * mul % mod * pow2[cnt] % mod);
		}
		// debug(bitset<3>(q), dp[q]);
	}
	cout << dp[(1 << N) - 1] << "\n";
}

int main() {
#ifndef LOCAL
	ios::sync_with_stdio(false);
    cin.tie(0);
#endif
    cout << fixed;
	cout.precision(20);
	srand((unsigned int)time(NULL));
#ifdef LOCAL
	//freopen("in.txt", "wt", stdout); //for tester
    freopen("in.txt", "rt", stdin);
#endif	
	solve();
#ifdef LOCAL
    cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
	return 0;
}

Submission Info

Judge Result