leetcode/InvertBinaryTree.py at master · doitfool/leetcode · GitHub

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"""
	@Project: leetcode
	@file: InvertBinaryTree.py
	@author: AC
	@time: 2016/5/4 0:42
	@Description:	Invert a binary tree.

                         4
                       /   \
                      2     7
                     / \   / \
                    1   3 6   9
                    to
                         4
                       /   \
                      7     2
                     / \   / \
                    9   6 3   1
"""

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

class Solution(object):
    def invertTree(self, root):
        """
        :type root: TreeNode
        :rtype: TreeNode
        """
        if root is None:
            return
        else:
            temp = root.left
            root.left = root.right
            root.right = temp
        self.invertTree(root.left)
        self.invertTree(root.right)
        return root