update Solution

Author: hanhaotian

BFS/MaximumDepthOfBinaryTree.py

@@ -28,3 +28,13 @@
 https://leetcode.com/problems/maximum-depth-of-binary-tree/description/
 
 """
+class Solution:
+    
+    def maxDepth(self, root: TreeNode) -> int:
+        if root is None: 
+            return 0 
+        else: 
+            left_height = self.maxDepth(root.left) 
+            right_height = self.maxDepth(root.right) 
+            return max(left_height, right_height) + 1 
+