Merge pull request TheAlgorithms#39 from akshaysharma096/master

dynamitechetan · web-flow · commit 0dbd2df11b70 · 2016-10-14T08:09:21.000+05:30
added isinstance check
diff --git a/traverals/binary_tree_traversals.py b/traverals/binary_tree_traversals.py
@@ -6,7 +6,6 @@
 
 
 class TreeNode:
-
 def __init__(self, data):
 self.data = data
 self.right = None
@@ -40,31 +39,32 @@ def build_tree():
 
 
 def pre_order(node):
- if not node:
+ if not isinstance(node, TreeNode) or not node:
+ print("Invalid input")
 return
 print(node.data, end=" ")
 pre_order(node.left)
 pre_order(node.right)
 
 
 def in_order(node):
- if not node:
+ if not isinstance(node, TreeNode) or not node:
 return
 in_order(node.left)
 print(node.data, end=" ")
 in_order(node.right)
 
 
 def post_order(node):
- if not node:
+ if not isinstance(node, TreeNode) or not node:
 return
 post_order(node.left)
 post_order(node.right)
 print(node.data, end=" ")
 
 
 def level_order(node):
- if not node:
+ if not isinstance(node, TreeNode) or not node:
 return
 q = queue.Queue()
 q.put(node)
@@ -79,6 +79,7 @@ def level_order(node):
 
 if __name__ == '__main__':
 import sys
+
 print("\n********* Binary Tree Traversals ************\n")
 # For python 2.x and 3.x compatibility: 3.x has not raw_input builtin
 # otherwise 2.x's input builtin function is too "smart"

-Original file line number
+Diff line change
 classTreeNode:
+-
 def__init__(self, data):
 self.data=data
 self.right=None
 defpre_order(node):
 -ifnotnode:
 +ifnotisinstance(node, TreeNode) ornotnode:
 +print("Invalid input")
 return
 print(node.data, end=" ")
 pre_order(node.left)
 pre_order(node.right)
 defin_order(node):
 -ifnotnode:
 +ifnotisinstance(node, TreeNode) ornotnode:
 return
 in_order(node.left)
 print(node.data, end=" ")
 in_order(node.right)
 defpost_order(node):
 -ifnotnode:
 +ifnotisinstance(node, TreeNode) ornotnode:
 return
 post_order(node.left)
 post_order(node.right)
 print(node.data, end=" ")
 deflevel_order(node):
 -ifnotnode:
 +ifnotisinstance(node, TreeNode) ornotnode:
 return
 q=queue.Queue()
 q.put(node)
 if__name__=='__main__':
 importsys
++
 print("\n********* Binary Tree Traversals ************\n")
 # For python 2.x and 3.x compatibility: 3.x has not raw_input builtin
 # otherwise 2.x's input builtin function is too "smart"