[653. Two Sum IV - Input is a BST] #leetcode

653.py

class Solution:
    cor = set()
    def findTarget(self, root, k):
        """
        :type root: TreeNode
        :type k: int
        :rtype: bool
        """
        if root is None:
            return False
        
        if root.val in self.cor:
            return True
        else:
            self.cor.add(k - root.val)
            return self.findTarget(root.left, k) or self.findTarget(root.right, k)