Hdu 1757A Simple Math Problem矩阵

构造个矩阵搞下就行了

a0 a1 a2 a3 a4 a5 a6 a7 a8 a9

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  0

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <string.h>
typedef long long LL;
using namespace std;
LL  vis[100];
LL  M;
struct Matrix
{
    LL  m[12][12];
};
LL  n;
Matrix Mul(Matrix a, Matrix b)
{
    Matrix ans;
    for (LL i = 0; i < 10; i++){
        for (LL j = 0; j < 10; j++){
            ans.m[i][j] = 0;
            for (LL k = 0; k < 10; k++){
                ans.m[i][j] += a.m[i][k] * b.m[k][j];
                ans.m[i][j] %= M;
            }
        }
    }
    return ans;
}

Matrix quick(Matrix a, LL b)
{
    Matrix ans;
    for (LL i = 0; i < 10; i++)
    for (LL j = 0; j < 10; j++)
        ans.m[i][j] = (i == j);
    while (b){
        if (b & 1) ans = Mul(ans, a);
        a = Mul(a, a);
        b >>= 1;
    }
    return ans;
}

Matrix init()
{
    for (LL i = 0; i < 10; i++)
        scanf("%d", &vis[i]);
    Matrix ans;
    for (LL i = 0; i < 10; i++)
    for (LL j = 0; j < 10; j++)
        ans.m[i][j] = 0;
    for (LL i = 0; i < 10; i++)
        ans.m[0][i] = vis[i];
    for (LL i = 1; i < 10; i++){
        ans.m[i][i - 1] = 1;
    }
    return ans;
}

void gao()
{
    LL t = n - 9;
    Matrix ans = init();
    ans = quick(ans, t);
    LL sum = 0;
    for (LL i = 0; i < 10; i++){
        sum += ans.m[0][i] * (9 - i);
        sum %= M;
    }
    cout << sum << endl;
}

int main()
{
    while (cin >> n >> M){
        if (n < 10){
            cout << n << endl;
            continue;
        }
        gao();
    }
    return 0;
}