Solution0226.py

# #Easy #Top_100_Liked_Questions #Depth_First_Search #Breadth_First_Search #Tree #Binary_Tree
# #Data_Structure_I_Day_12_Tree #Level_2_Day_6_Tree #Udemy_Tree_Stack_Queue
# #Top_Interview_150_Binary_Tree_General #Big_O_Time_O(n)_Space_O(n)
# #2025_07_25_Time_0_ms_(100.00%)_Space_17.94_MB_(9.36%)

from typing import Optional

class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
        if root is None:
            return None
        
        # Swap the left and right children
        temp = root.left
        root.left = self.invertTree(root.right)
        root.right = self.invertTree(temp)
        
        return root