Submission #11375148

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Source Code Expand

#include<cstdio>
#include<cstring>
using namespace std;
typedef long long ll;
const int N =35;
const int mod = 1e9 + 7;
int L, m, k;
ll n;
bool v[N];
struct sq{
	int a[N][N];
	sq() { memset(a, 0, sizeof(a)); }
	sq operator * (const sq &b) const
	{
		int i, j, k;
		sq c;
		for (i = 0; i <= L; i++)
			for (j = 0; j <= L; j++)
				for (k = 0; k <= L; k++)
					c.a[i][j] = (1LL * a[i][k] * b.a[k][j] % mod + c.a[i][j]) % mod;
		return c;
	}
};
sq A, an;
void dfs(int x, int nw, int da)
{
	if (!(x ^ m))
	{
		v[da] = 1;
		int ne = da >> 1;
		A.a[ne][da] = 1;
		if (nw ^ k || da & 1)
			A.a[ne | (1 << (m - 1))][da] = 1;
		return;
	}
	dfs(x + 1, nw, da);
	if (nw < k)
		dfs(x + 1, nw + 1, da | (1 << x));
}
void ksm()
{
	an = A;
	if (!n)
		return;
	for (n--; n; n >>= 1, A = A * A)
		if (n & 1)
			an = an * A;
}
int main()
{
	int i, s = 0;
	scanf("%lld%d%d", &n, &m, &k);
	L = (1 << m) - 1;
	dfs(0, 0, 0);
	ksm();
	for (i = 0; i <= L; i++)
		if (v[i])
			s = (1LL * s + an.a[i][i]) % mod;
	printf("%d", s);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:52:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld%d%d", &n, &m, &k);
                               ^

Judge Result