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
", ans);
    }
    return 0;
}