伸展树 都知道如果使用二叉查找树树平衡度不好则会降低查询效率，所以我们要维护二叉树的平衡性，即TreapTree 、SplayTree 、AVL、红黑等，本文介绍伸展树的平衡原理和核心代码 -Tree stretching all know if you use binary search tree tree balance will not reduce the query efficiency, and therefore we have to safeguard the balan