all tasks

Task/Tree-traversal/Python/tree-traversal.py

@@ -0,0 +1,55 @@
+from collections import namedtuple
+from sys import stdout
+
+Node = namedtuple('Node', 'data, left, right')
+tree = Node(1,
+            Node(2,
+                 Node(4,
+                      Node(7, None, None),
+                      None),
+                 Node(5, None, None)),
+            Node(3,
+                 Node(6,
+                      Node(8, None, None),
+                      Node(9, None, None)),
+                 None))
+
+def printwithspace(i):
+    stdout.write("%i " % i)
+
+def preorder(node, visitor = printwithspace):
+    if node is not None:
+        visitor(node.data)
+        preorder(node.left, visitor)
+        preorder(node.right, visitor)
+
+def inorder(node, visitor = printwithspace):
+    if node is not None:
+        inorder(node.left, visitor)
+        visitor(node.data)
+        inorder(node.right, visitor)
+
+def postorder(node, visitor = printwithspace):
+    if node is not None:
+        postorder(node.left, visitor)
+        postorder(node.right, visitor)
+        visitor(node.data)
+
+def levelorder(node, more=None, visitor = printwithspace):
+    if node is not None:
+        if more is None:
+            more = []
+        more += [node.left, node.right]
+        visitor(node.data)
+    if more:
+        levelorder(more[0], more[1:], visitor)
+
+stdout.write('  preorder: ')
+preorder(tree)
+stdout.write('\n   inorder: ')
+inorder(tree)
+stdout.write('\n postorder: ')
+postorder(tree)
+stdout.write('\nlevelorder: ')
+levelorder(tree)
+stdout.write('\n')