Submission #1361651

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Source Code Expand

#include<cstdio>
#include<algorithm>

using namespace std;

const long long mod = 1000000007;

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

void input(){
	scanf("%d%d", &N, &M);
	for(int i = 0; i < M; ++i){
		int x, y;
		scanf("%d%d", &x, &y);
		x--;
		y--;
		G[x][y] = true;
	}
}

long long dp[1 << 15];

inline long long f(int n){
	return (1 << n) - 1;
}

inline int count(int v, int S){
	int res = 0;
	for(int i = 0; i < N; ++i){
		if((S >> i) & 1){
			if(G[v][i]) res++;
		}
	}
	return res;
}

bool check(int S){
	int x = (S & 1) ^ ((S & 2) >> 1);
	return x == 0;
}

long long solve(){
	dp[0] = 1;
	int mask = (1 << N) - 1;
	for(int S = 1; S < (1 << N); ++S){
		if(!check(S)) continue;
		for(int S2 = (S - 1) & S; ; S2 = (S2 - 1) & S){
			if(!check(S2)) continue;
			long long coe = 1;
			for(int v = 0; v < N; ++v){
				if((S >> v) & 1) continue;
				int cnt = count(v, S - S2);
				coe *= f(cnt);
				coe %= mod;
			}
			for(int v = 0; v < N; ++v){
				int x = S - S2;
				if((x >> v) & 1){
					int cnt = count(v, mask - S);
					coe *= (f(cnt) + 1);
					coe %= mod;
				}
			}
			dp[S] += dp[S2] * coe;
			dp[S] %= mod;
			if(S2 == 0) break;
		}
	}
	long long all = 1;
	for(int i = 0; i < M; ++i){
		all *= 2;
		all %= mod;
	}
	long long ans = all - dp[mask];
	ans %= mod;
	ans += mod;
	ans %= mod;
	return ans;
}

int main(){
	input();
	long long ans = solve();
	printf("%lld\n", ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘void input()’:
./Main.cpp:13:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &N, &M);
                       ^
./Main.cpp:16:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &x, &y);
                        ^

Judge Result