[prograsshopper] Week 10 Solutions

invert-binary-tree/prograsshopper.py

@@ -0,0 +1,23 @@
+# 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]:
+        # Time Complexity: O(N) / Space Complexity: O(N)
+        if not root or (not root.left and not root.right):
+            return root
+
+        def invert(node: TreeNode):
+            if not node:
+                return
+            node.right, node.left = node.left, node.right
+            if node.right:
+                invert(node.right)
+            if node.left:
+                invert(node.left)
+
+        invert(root)
+        return root