leetcode

Convert BST to Greater Tree

Convert BST to Greater Tree

Recursive Version - 88ms

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# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def __init__(self):
        self.lSum = 0    
    def convertBST(self, root):
        """
        :type root: TreeNode
        :rtype: TreeNode
        """
        if not root:
            return None
        self.convertBST(root.right)
        self.lSum += root.val
        root.val = self.lSum
        self.convertBST(root.left)
        return root

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