HDU1757矩阵快速幂

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#define LL long long
using namespace std;
const int N = 10;//矩阵大小
int mod;
int k;//矩阵的幂
int a[15];

struct Matrix
{
    LL mat[N][N];//二维数组存储矩阵
    Matrix operator*(const Matrix &m)const
    {
        Matrix temp;
        for(int i = 0; i < N;i++)
        {
            for(int j = 0; j < N; j++)
            {
                temp.mat[i][j] = 0;
                for(int k = 0; k < N; k++)
                {
                    temp.mat[i][j]+=mat[i][k]*m.mat[k][j]%mod;
                    temp.mat[i][j]%=mod;
                }
            }
        }
        return temp;
    }

};
void Init(Matrix &m)
{
    memset(m.mat,0,sizeof(m.mat));
    for(int i = 0; i < N;i++)
        m.mat[0][i] = a[i];
    for(int i = 1; i < N; i++)
    {
        m.mat[i][i-1] = 1;
    }
}
LL qpow(Matrix &m,LL k)
{
    Matrix ans;
    memset(ans.mat,0,sizeof(ans.mat));
    for(int i = 0; i < N; i++)
        ans.mat[i][i] = 1;
    while(k)
    {
        if(k&1)ans = ans * m;
        m = m*m;
        k>>=1;
    }
    LL sum = 0;
    int f[10];
    for(int i = 0; i < N; i++)
        f[i] = N-i-1;
    for(int i = 0; i < N; i++)
    {
        sum+=ans.mat[0][i]*f[i]%mod;
        sum%=mod;
    }
    return sum%mod;
}
int main()
{
    while(scanf("%d%d",&k,&mod)!=EOF)
    {
        for(int i = 0; i <= 9; i++)
            scanf("%d",&a[i]);
        if(k<10)
        {
            printf("%d
",k%mod);
        }
        else
        {
            Matrix m;
            Init(m);
            cout<<qpow(m,k-9)<<endl;
        }
    }
    return 0;
}