Hdu1575Tr A矩阵

矩阵快速幂，就是快速幂的乘法变成矩阵乘法，其余的都一样。

#include <cstdio>

#include <algorithm>

#include <iostream>

#include <string.h>

using namespace std;

const int mod = 9973;

const int maxn = 12;

struct Matrix

{

    int m[maxn][maxn];

};

int n;

Matrix Mul(Matrix a, Matrix b)

{

    Matrix ans; 

    for (int i = 0; i < n; i++){

        for (int j = 0; j < n; j++){

            ans.m[i][j] = 0;

            for (int k = 0; k < n; k++){

                ans.m[i][j] += (a.m[i][k] * b.m[k][j]);

                ans.m[i][j] %= mod;

            }

        }

    }

    return ans;

}



Matrix fast(Matrix  a, int sum)

{

    Matrix  ans;

    for (int i = 0; i < n;i++)

    for (int j = 0; j < n; j++)

        ans.m[i][j] = (i == j);

    while (sum){

        if (sum & 1) ans = Mul(ans, a);

        a = Mul(a, a);

        sum /= 2;

    }

    return ans;

}



int main()

{

    int t,k;

    cin >> t;

    Matrix a;

    while (t--){

        cin >> n >> k;

        for (int i = 0; i < n;i++)

        for (int j = 0; j < n; j++)

            cin >> a.m[i][j];

        Matrix gao = fast(a, k);

        int ans = 0;

        for (int i = 0; i < n; i++)

            ans += gao.m[i][i], ans %= mod;

        printf("%d\n", ans);

    }

    return 0;

}