feat: Solve invert-binary-tree problem

Author: hu6r1s

invert-binary-tree/hu6r1s.py

@@ -0,0 +1,14 @@
+# 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.left, root.right = root.right, root.left
+        self.invertTree(root.left)
+        self.invertTree(root.right)
+        return root