矩阵乘法

struct matrix
{
    int a[10][10];
    matrix () { memset(a, 0, sizeof(a)); }
    inline friend matrix operator *(matrix A, matrix B)
    {
        matrix C;
        for (int i = 1; i <= n; ++i)
            for (int k = 1; k <= n; ++k)
                for (int j = 1; j <= n; ++j)
                    C.a[i][j] = (C.a[i][j] + A.a[i][k] * B.a[k][j]) % mod;
        return C;
    }
}; matrix ans, base;
void qbow(int b)
{
    while (b)
    {
        if (b & 1) ans = ans * base;
        base = base * base;
        b >>= 1;
    }
}