如果用包含柔性数组的结构体组成一个数组，那么应该怎么声明与定义？

typedef struct _user{
    int total_score;
    int pefect_score;
    int scores[];
}User;

int main()
{
    int user_num, problem_num;
    scanf("%d %d", &user_num, &problem_num);
    User* users = (User*)malloc(user_num * (sizeof(User) + problem_num*sizeof(int)));

    return 0;
}