LeetCode 226. Invert Binary Tree - Python

LeetCode 226. Invert Binary Tree - Python

 

 

Invert a binary tree.

 

Example:

Input:

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

Output:

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

 

 

Solution :

class Solution(object):
    def invertTree(self, root):
        stack = [root]
        while stack:
            node = stack.pop()
            if node:
                node.left, node.right = node.right, node.left
                stack += node.left, node.right
        return root

 

 

 

(솔루션 출처)

 https://gist.github.com/ryuji0123/

# 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 traverse(self, root):
    #     if not root: return
    #     root.left, root.right = root.right, root.left
    #     self.invertTree(root.left)
    #     self.invertTree(root.right)
        
    def invertTree(self, root):
        """
        :type root: TreeNode
        :rtype: TreeNode
        """
        # My answer
        # self.traverse(root)
        # return root
        
        # Another answer
        # if root:
        #     root.left, root.right = self.invertTree(root.right), self.invertTree(root.left)
        #     return root
        
        stack = [root]
        while stack:
            node = stack.pop()
            if node:
                node.left, node.right = node.right, node.left
                stack += node.left, node.right
        return root

 

(참고 사이트)

이진트리 학습 구조 : https://chohyeonkeun.github.io/2019/07/04/190704-datastructure-binarytree/

이진트리 반전시키기 : https://www.youtube.com/watch?v=rkt34Yt4KIo

self, __init__ 관련 질문 답변 : https://www.inflearn.com/questions/4642

__init__() 메서드와 self 인자 : https://dojang.io/mod/page/view.php?id=2373

객체지향 : https://www.youtube.com/watch?v=gqVIa_NDBsk