Update binary_tree_preorder_traversal.py

yingl · web-flow · commit 4c463e40d50b · 2017-04-25T14:08:45.000+08:00
diff --git a/binary_tree_preorder_traversal.py b/binary_tree_preorder_traversal.py
@@ -1,4 +1,4 @@
-# -*- coding: utf-8 -*-
+# coding: utf-8
 
 class Solution:
     def __init__(self):
@@ -14,4 +14,6 @@ def preorderTraversal(self, root):
             self.ret.append(root.val)
             self.preorderTraversal(root.left)
             self.preorderTraversal(root.right)
-        return self.ret
+        return self.ret
+
+# easy: http://lintcode.com/problem/binary-tree-preorder-traversal
