Submission #2712484

---

Source Code Expand

n,m = (int(i) for i in input().split())
a = [[i,2**i] for i in range(n)]
b = [0 for i in range(n)]
dp = [1]+[0 for i in range(2**n-1)]
for _ in range(m):
	x,y = (int(i) for i in input().split())
	b[x-1]+=a[y-1][1]
for i in range(2**n):
	for j,j2 in a:
		if i&b[j]==0 and i&j2==0: dp[i | j2]+=dp[i]
print(dp[-1])

Submission Info

Judge Result