leval_order_traversal.py

# Python program to print level order traversal using Queue

# A node structure
class Node:
    # A utility function to create a new node
    def __init__(self, key):
        self.data = key
        self.left = None
        self.right = None


# Iterative Method to print the height of binary tree
def printLevelOrder(root):
    # Base Case
    if root is None:
        return

    # Create an empty queue for level order traversal
    queue = []

    # Enqueue Root and initialize height
    queue.append(root)

    while (len(queue) > 0):
        # Print front of queue and remove it from queue
        print
        queue[0].data,
        node = queue.pop(0)

        # Enqueue left child
        if node.left is not None:
            queue.append(node.left)

            # Enqueue right child
        if node.right is not None:
            queue.append(node.right)

            # Driver Program to practiceset above function


root = Node(1)
root.left = Node(2)
root.right = Node(3)
root.left.left = Node(4)
root.left.right = Node(5)

print("Level Order Traversal of binary tree is -")
printLevelOrder(root)
# This code is contributed by Nikhil Kumar Singh(nickzuck_007)