solved invert-bin-tree.

Author: sangbeenmoon

invert-binary-tree/sangbeenmoon.py

@@ -0,0 +1,21 @@
+# 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 root
+        
+
+        def go(cur: TreeNode) -> Optional[TreeNode]:
+            if not cur:
+                return cur
+            res = TreeNode(cur.val)
+            res.left = go(cur.right)
+            res.right = go(cur.left)
+            return res
+
+        return go(root)