Merge pull request #5 from hanhaotian/master

update Solution

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 
+

Tree/KthSmallestElementInABST.py

@@ -56,24 +56,18 @@
 #         self.left = None
 #         self.right = None
 
-class Solution(object):
-    def kthSmallest(self, root, k):
-        """
-        :type root: TreeNode
-        :type k: int
-        :rtype: int
-        """
-        self.inorder_result = []
-
-        def inorder(root):
-            if root.left:
-                inorder(root.left)
-
-            self.inorder_result.append(root.val)
-
-            if root.right:
-                inorder(root.right)
-
-        inorder(root)
-
-        return self.inorder_result[k-1]
+class Solution:
+
+    def find_data(self, root: TreeNode):
+
+        if root is None:
+            return
+        Solution.find_data(self,root.left)
+        self.data.append(root.val)
+        Solution.find_data(self,root.right)
+        return
+
+    def kthSmallest(self, root: TreeNode, k: int) -> int:
+        self.data = []
+        Solution.find_data(self, root)
+        return self.data[k-1]