该程序可以帮助初学者了解AVL树。输入一组关键字序列，并以此顺序建立一棵平衡二叉树，并在建树过程中用逆中序法输出每次插入新结点后的平衡二叉树形状。-The program can help beginners learn AVL tree. Enter a set of keywords sequences and in this order to establish balanced binary tree, and the achievements in the process of usi