题目
Given the root node of a binary search tree (BST) and a value. You need to find the node in the BST that the node’s value equals the given value. Return the subtree rooted with that node. If such node doesn’t exist, you should return NULL.
解题思路
递归和非递归两种做法，如果当前节点的值为要找的值则返回，大于则在左子树，小于在右子树
代码
非递归
class Solution:
def searchBST(self, root: TreeNode, val: int) -> TreeNode:
if not root:
return None
while root:
if root.val == val:
return root
if root.val > val:
root = root.left
else:
root = root.right
递归
class Solution:
def searchBST(self, root: TreeNode, val: int) -> TreeNode:
if not root:
return None
if root.val == val:
return root
if root.val > val:
return self.searchBST(root.left, val)
return self.searchBST(root.right, val)
