hdu1757矩阵快速幂

这题不错，开始看题目，以为是道水题，花几分钟打了个暴搜，果断runtime error，栈溢出。于是马上找规律，发现可以转换成矩阵乘法和快速幂解决，不过由于审题不清，搞错了a0...a9的顺序，调了老半天才发现。。。。

/*
 * hdu1757/win.cpp
 * Created on: 2012-7-9
 * Author    : ben
 */
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <queue>
using namespace std;

const int MAX_ORDER = 11;
int MOD;
typedef int typec;
typedef struct MyMatrix {
    int order;
    typec num[MAX_ORDER][MAX_ORDER];
    MyMatrix(int ord) {
        order = ord;
    }
    void init() {
        for (int i = 0; i < order; i++) {
            for (int j = 0; j < order; j++) {
                num[i][j] = 0;
            }
        }
    }
}MyMatrix;

MyMatrix operator*(MyMatrix ma, MyMatrix mb) {
    int ord = ma.order;
    MyMatrix numc(ord);
    numc.init();
    int i, j, k;
    for (i = 0; i < ord; i++) {
        for (j = 0; j < ord; j++) {
            for (k = 0; k < ord; k++) {
                numc.num[i][j] += ma.num[i][k] * mb.num[k][j];
                numc.num[i][j] %= MOD;
            }
        }    }
    return numc;
}

MyMatrix mpow(MyMatrix ma, int x) {
    int ord = ma.order;
    MyMatrix numc(ord);
    numc.init();
    for (int i = 0; i < ord; i++) {
        numc.num[i][i] = 1;
    }
    for (; x; x >>= 1) {
        if (x & 1) {
            numc = numc * ma;
        }
        ma = ma * ma;
    }
    return numc;
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int k;
    MyMatrix matrix(10);
    matrix.init();
    for(int i = 0; i < 9; i++) {
        matrix.num[i + 1][i] = 1;
    }
    while(scanf("%d%d", &k, &MOD) == 2) {
        for(int i = 9; i >= 0; i--) {
            scanf("%d", &matrix.num[i][9]);
        }
        MyMatrix ret = mpow(matrix, k - 9);
        int ans = 0;
        for(int i = 1; i < 10; i++) {
            ans += (i * ret.num[i][9]) % MOD;
            ans %= MOD;
        }
        printf("%d\n", ans);
    }
    return 0;
}