solve: invertBinaryTree

Author: GaggleHelena

invert-binary-tree/yolophg.py

@@ -0,0 +1,18 @@
+# Time Complexity: O(N) - visit each node once.
+# Space Complexity: O(N) - skewed tree, recursion goes N levels deep.
+
+class Solution:
+    def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
+        if root is None:
+            return root  # If the tree is empty, just return None.
+        
+        # swap left and right child nodes.
+        root.left, root.right = root.right, root.left
+        
+        # recursively invert left and right subtrees.
+        if root.left:
+            self.invertTree(root.left)
+        if root.right:
+            self.invertTree(root.right)
+        
+        return root