vijos Warcraft III 守望者的烦恼

题解

转移方程好写吧

一个一维递推式

然后我们可以构造矩阵优化

嗯，最近学一下递推优化

代码

#include<cstdio>
#include<cstring>
#include<algorithm>
#define mod 7777777
int K,n;
#define LL long long
const int maxn = 11;
struct matrix {
	int a[maxn][maxn];int c,r;
	void in(int x,int y) {
		r = x,c = y;
	}
	matrix() {
		c = 0,r = 0;
		memset(a,0,sizeof a); n = 0 ;
	}
} ans,tmp;
matrix operator * (const matrix A,const matrix B) {
	matrix ret; ret.in(A.r,B.c);
	for(int i = 0; i < ret.r;++ i)
		for(int j = 0;j < ret.c;++ j)
			for(int k = 0;k < A.c;++ k)
			 	ret.a[i][j] = (ret.a[i][j] + ((long long )A.a[i][k] * B.a[k][j] % mod) )% mod;
	return ret;
}
int dp[maxn];
matrix pow(matrix a,int k) {
	matrix ret;
	ret.in(K,K);
	for(int i = 0;i < K;++ i) ret.a[i][i] = 1;
	for(;k;k >>= 1,a = a * a)
		if(k & 1) ret = ret * a;
	return ret;
}
int main() {
	scanf("%d%d",&K,&n);
	tmp.in(K,K);
	for(int i = 0;i < K;++ i)  tmp.a[i][0] = 1;
	for(int i = 1;i < K;++ i)  tmp.a[i - 1][i] = 1;
	tmp = pow(tmp,n);
	ans.in(1,K);
	ans.a[0][0] = 1;
	ans = ans * tmp;
	printf("%lld\n",ans.a[0][0]);
	return 0;
}