2025-01-06 13:28

Status: child

Tags: leetcode leetcode-easy trees binary-trees computer-science Leetcode

Invert Binary Tree

Code

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
 
class Solution(object):
    def invertTree(self, root):
        """
        :type root: Optional[TreeNode]
        :rtype: Optional[TreeNode]
        """
        if not root:
            return 
 
        temp = root.left
        root.left = root.right
        root.right = temp
        self.invertTree(root.left)
        self.invertTree(root.right)
        return root

Explanation

1. If the root is None, return

2. Set tmp = root.left(you’ll see why)

3. root.left = root.right because we’re inverting the positions

4. root.right = tmp because root.left got overidden

5. Call self.invertTree(root.left) and self.invertTree(root.right)

6. Return root

References