Invert Binary Tree
Total Accepted: 39609 Total Submissions: 100664 Difficulty: Easy
Invert a binary tree.
4 / \ 2 7 / \ / \ 1 3 6 9
to
4 / \ 7 2 / \ / \ 9 6 3 1
Trivia:
This problem was inspired by this original tweet by Max Howell:
Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so fuck off.
Code
# 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
root.left, root.right = root.right, root.left
if root.left:
self.invertTree(root.left)
if root.right:
self.invertTree(root.right)
return root