leetcode_python_150/226_Invert_Binary_Tree.py at main · Ishazaka/leetcode_python_150 · GitHub

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#1st way

# 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 not root:
            return None
        queue = deque([root])
        while queue:
            node = queue.popleft()
            node.left, node.right = node.right, node.left
            if node.left:
                queue.append(node.left)
            if node.right:
                queue.append(node.right)
        return root


# 2nd way

# 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 not root: return None

        root.left, root.right = root.right, root.left

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

        return root