hdu 1757 A Simple Math Problem 矩阵优化+快速幂

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int  n=10;
int kt,m;

struct Matrix
{
int mp

;
};

Matrix mul(Matrix a,Matrix b)
{
int i,j,k;
Matrix c;

for(i=0; i<10; i++)
for(j=0; j<10; j++)
{
c.mp[i][j]=0;
for(k=0; k<10; k++)
{
c.mp[i][j]=(c.mp[i][j]+a.mp[i][k]*b.mp[k][j])%m;
}
}
return c;
}

Matrix pow(Matrix t,int x)
{
if(x==1) return t;
Matrix c;
c=pow(t,x/2);
c=mul(c,c);
if(x&1)
return mul(c,t);
else
return c;
}

int main()
{
int i,j,ans;
Matrix a,t;
while(~scanf("%d%d",&kt,&m))
{
for(i=0;i<n;i++)
scanf("%d",&a.mp[0][i]);
if(kt<10)
{
printf("%d\n",kt%m);
continue;
}

for(i=1;i<n;i++)
for(j=0;j<n;j++)
{
if(i==j+1) a.mp[i][j]=1;
else a.mp[i][j]=0;
}
t=pow(a,kt-9);
for(i=0,ans=0;i<n;i++)
{
//printf("%d\n",ans);
ans=(ans+t.mp[0][i]*(n-i-1))%m;
}
printf("%d\n",ans);
}
return 0;
}