矩阵乘法模板

// 模板矩阵
LL A[10][10] = {
};
struct Matrix {
    void mul(LL a[10][10], LL b[10][10], LL c[10][10]) {
        LL tmp[10][10] {};
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < n; ++j) {
                for (int k = 0; k < n; ++k) {
                    tmp[i][j] = (tmp[i][j] + a[i][k] * b[k][j]) % P;
                }
            }
        }
        memcpy(c, tmp, sizeof tmp);
    }
    void qmi(LL f[10][10], LL n) {
        while (n) {
            if (n & 1) {
                mul(A, f, f);
            }
            mul(A, A, A);
            n >>= 1;
        }
    }
    int n;  // 矩阵大小
    Matrix(int sz): n(sz) {};
};