Modernize Python 2 code to get ready for Python 3

data_structures/Graph/Graph.py

@@ -1,3 +1,4 @@
+from __future__ import print_function
 # Author: OMKAR PATHAK
 
 # We can use Python's dictionary for constructing the graph
@@ -15,7 +16,7 @@ class AdjacencyList(object):
 
     def printList(self):
         for i  in self.List:
-            print(i,'->',' -> '.join([str(j) for j in self.List[i]]))
+            print((i,'->',' -> '.join([str(j) for j in self.List[i]])))
 
 if __name__ == '__main__':
     al = AdjacencyList()

data_structures/Graph/even_tree.py

@@ -12,6 +12,7 @@ Constraints
 Note: The tree input will be such that it can always be decomposed into
 components containing an even number of nodes.
 """
+from __future__ import print_function
 # pylint: disable=invalid-name
 from collections import defaultdict
 
@@ -66,4 +67,4 @@ if __name__ == '__main__':
         tree[u].append(v)
         tree[v].append(u)
     even_tree()
-    print len(cuts) - 1
+    print(len(cuts) - 1)