[LeetCode][Python3] 226. Invert Binary Tree

Problem :

https://leetcode.com/problems/invert-binary-tree/description/

My Solution :

# Definition for a binary tree node.

# class TreeNode:

# def __init__(self, x):

# self.val = x

# self.left = None

# self.right = None

class Solution:

def invertTree(self, root):

"""

:type root: TreeNode

:rtype: TreeNode

"""

if root:

root.left, root.right = (

self.invertTree(root.right), self.invertTree(root.left))

return root

Comment :

위 방법은 Recursion을 활용한 것이다. 80칸 넘어가는걸 괄호 열고 개행했는데 뭐가 최선의 컨벤션인지 잘 모르겠다.

아래는 Iterative이다. Stack을 쓰든 Queue를 쓰든 아무런 상관이 없다.

My Solution2 :

# Definition for a binary tree node.

# class TreeNode:

# def __init__(self, x):

# self.val = x

# self.left = None

# self.right = None

class Solution:

def invertTree(self, root):

"""

:type root: TreeNode

:rtype: TreeNode

"""

stack = [root]

while stack:

node = stack.pop()

if node:

node.left, node.right = node.right, node.left

stack.extend([node.left, node.right])

return root