function.py

# Python program to check if a binary tree complete or not
 
# Tree node structure
class Node:
 
    # Contructor to create a new node
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None
 
 
# This function counts the number of nodes in a binary tree
def countNodes(root):
    if root is None:
        return 0
    return (1+ countNodes(root.left) + countNodes(root.right))
 
# This function checks if binary tree is complete or not
def isComplete(root, index, number_nodes):
     
    # An empty is complete
    if root is None:
        return True
     
    # If index assigned to current nodes is more than
    # number of nodes in tree, then tree is not complete
    if index >= number_nodes :
        return False
     
    # Recur for left and right subtress
    return (isComplete(root.left , 2*index+1 , number_nodes)
        and isComplete(root.right, 2*index+2, number_nodes)
          )
 
# Driver Program 
 
root = Node(1)
root.left = Node(2)
root.right = Node(3)
root.left.left = Node(4)
root.left.right = Node(5)
root.right.right = Node(6)
 
node_count = countNodes(root)
index = 0
 
if isComplete(root, index, node_count):
    print "The Binary Tree is complete"
else:
    print "The Binary Tree is not complete"