700. Search in a Binary Search Tree.py

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def searchBST(self, root: TreeNode, val: int) -> TreeNode:
        if not root:
            return None
        if val > root.val:
            return self.searchBST(root.right,val)
        elif val < root.val:
            return self.searchBST(root.left,val)
        else:
            return root