HDU1757-矩阵相乘

强大的矩阵相乘啊！矩阵第一行会记录下 a0~a9 乘过的个数！

#include<iostream>
using namespace std;
__int64 k,m;
struct mat
{
int mar[10][10];
}a,b,tmp;

mat matrixmul(mat a,mat b)
{
int i,j,k;
for(i = 0;i < 10;i++)
for(j = 0;j < 10;j++)
{
tmp.mar[i][j] = 0;
for(k = 0;k < 10;k++)
tmp.mar[i][j] += (a.mar[i][k] * b.mar[k][j]) % m;
tmp.mar[i][j] %= m;
}
return tmp;
}

void matrix_binary()
{
while(k)
{
if(k & 1)
b = matrixmul(b,a);
a = matrixmul(a,a);
k = k >> 1;
}
}
int main()
{
int i;
while (scanf("%I64d%I64d",&k,&m) != EOF)
{
memset(a.mar,0,sizeof(a.mar));
for(i = 1;i < 10;i++)
a.mar[i][i-1] = 1;
memset(b.mar,0,sizeof(b.mar));
for(i = 0;i < 10;i++)
b.mar[i][i] = 1;
for(i = 0;i < 10;i++)
scanf("%d",&a.mar[0][i]);
if(k < 10)
{
printf("%d\n", k % m);
continue;
}
k -= 9;
matrix_binary();
int res = 0;
for(i = 0;i < 10;i++)
res += (b.mar[0][i] * (9-i)) % m;
printf("%d\n",res%m);
}
return 0;
}