Submission #2243111

---

Source Code Expand

#include <bits/stdc++.h>
using namespace std;

#define debug(...) fprintf(stderr, __VA_ARGS__)

const int mod = 1e9 + 7;

int n, m;
int two[300 + 5], adj[15 + 5], dp[(1 << 15) + 5];

int main() {
	scanf("%d%d", &n, &m);
	two[0] = 1;
	for (int i = 0; i < m; ++i) two[i + 1] = (two[i] << 1) % mod;
//	for (int i = 0; i <= m; ++i) debug("%d %d\n", i, two[i]);
	for (int i = 0; i < m; ++i) {
		int x, y;
		scanf("%d%d", &x, &y), --x, --y;
		adj[x] |= 1 << y;
//		adj[y] |= 1 << x;
	}
//	for (int i = 0; i < n; ++i) debug("%d %d\n", i, adj[i]);
	dp[0] = 1;
	for (int S = 1; S < (1 << n); ++S) {
		if ((S & 1) != (S >> 1 & 1)) continue;
		for (int T = S; T; (--T) &= S) {
			if ((T & 1) != (T >> 1 & 1)) continue;
//			debug("%d %d\n", S, T);
			int ways = 1, U = S ^ T;
			for (int i = 0; i < n; ++i)
				if (S >> i & 1) {
					if (T >> i & 1) ways = (long long)ways * two[__builtin_popcount(adj[i] & U)] % mod;
					else ways = (long long)ways * (two[__builtin_popcount(adj[i] & T)] - 1) % mod;
				}
			(dp[S] += (long long)dp[S ^ T] * ways % mod) %= mod;
		}
	}
//	for (int i = 0; i < (1 << n); ++i) debug("%d\n", dp[i]);
	printf("%d\n", (two[m] - dp[(1 << n) - 1] + mod) % mod);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:12:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
                       ^
./Main.cpp:18:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &x, &y), --x, --y;
                                  ^

Judge Result