AVLtree 同时实现了avl树的插入和删除算法，严格测试正确性，同时提供递归和非递归，算法可读性非常强 如有疑问可与作者联系qlaraya@gmail.com-AVLtree while achieving the avl tree insertion and deletion algorithms, rigorous testing accuracy, while providing recursive and non recursive algorithm is very str