HDU 1757 A Simple Math Problem

/*matrix a={ 
{0,1,0,0,0,0,0,0,0,0}, 
{0,0,1,0,0,0,0,0,0,0}, 
{0,0,0,1,0,0,0,0,0,0}, 
{0,0,0,0,1,0,0,0,0,0}, 
{0,0,0,0,0,1,0,0,0,0}, 
{0,0,0,0,0,0,1,0,0,0}, 
{0,0,0,0,0,0,0,1,0,0},
{0,0,0,0,0,0,0,0,1,0}, 
{0,0,0,0,0,0,0,0,0,1},
{1,1,1,1,1,1,1,1,1,1}, 
}; */

#include <cstdio>
#include <iostream>
#define maxn 15
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
struct matrix{
    int v[maxn][maxn];
    void init(){memset(v,0,sizeof v);}
}a,b;
matrix mul(matrix a,matrix b,int l,int m,int n,int mod){
    matrix c; c.init();
    rep(i,l)rep(j,m)rep(k,n)c.v[i][j]=(c.v[i][j]+(a.v[i][k]*b.v[k][j])%mod)%mod;
    return c;
}
matrix power(matrix a,int l,int m,int n,int x,int mod){
    if(x==1)return a;
    matrix tmp=power(a,l,m,n,x>>1,mod);
    tmp=mul(tmp,tmp,l,m,n,mod);
    if(x&1)tmp=mul(tmp,a,l,m,n,mod);
    return tmp;
}
int main(){
    int m,n;
    while(~scanf("%d%d",&n,&m)){
        a.init();
        for(int i=0;i<=8;i++)a.v[i][i+1]=1;
        for(int i=9;~i;i--)scanf("%d",&a.v[9][i]);
        if(n<=9){printf("%d
",n%m);continue;}
        for(int i=0;i<=9;i++)b.v[i][0]=i;
        a=power(a,10,10,10,n-9,m);
        b=mul(a,b,10,1,10,m);
        printf("%d
",b.v[9][0]);
    }
    return 0;
}