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 
     
      #include 
      
       #include 
       
        #include 
        
         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;}