Submission #1946065

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Source Code Expand

#include<cstdio>
#include<algorithm>
using namespace std;
int D[1 << 15];
int n, E[15], Mod = 1000000007, C[1 << 15], res = 1;
int main() {
	int i, j, m, a, b;
	scanf("%d%d", &n,&m);
	for (i = 0; i < m; i++) {
		scanf("%d%d", &a, &b);
		a--, b--;
		E[a] |= (1 << b);
		res = res * 2 % Mod;
	}
	for (i = 0; i < n; i++)for (j = 0; j < (1 << n); j++)if ((j >> i) & 1)C[j]++;
	D[0] = 1;
	for (i = 0; i < (1 << n); i++) {
		int bb = (1 << n) - 1 - i;
		if (!D[i])continue;
		for (int mask = bb; mask; mask = (mask - 1)&bb) {
			int rem = (1 << n) - 1 - i - mask;
			if ((mask & 3) && (mask & 3) != 3)continue;
			int r = D[i];
			for (j = 0; j < n; j++) {
				if (!((i | mask)&(1 << j))) {
					r = (long long)r * ((1 << C[E[j] & mask]) - 1) % Mod;
					continue;
				}
				if ((mask >> j) & 1) {
					r = ((long long)r << C[rem & E[j]]) % Mod;
				}
			}
			D[i | mask] = (D[i | mask] + r) % Mod;
		}
	}
	printf("%d\n", (res + Mod - D[(1 << n) - 1]) % Mod);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:8:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n,&m);
                      ^
./Main.cpp:10:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
                        ^

Judge Result