二叉搜索树(Binary Search Tree)是满足如下性质的二叉树：

①若它的左子树非空，则左子树上所有结点的值均小于根结点的值；

②若它的右子树非空，则右子树上所有结点的值均大于根结点的值；

③左、右子树本身又各是一棵二叉搜索树。-Binary Search Tree (Binary Search Tree) is to meet the nature of the binary tree as follows: ① If its non-empty left subtree, then the left sub-tree of all nodes is less than the value of the value of root node　② if it the right subtree is not empty, then the right sub-tree of all nodes greater than the value of the value of root node　③ the left and right subtree is the tree itself is the binary search tree.