left view iter python

# http://code2begin.blogspot.com
# Program to Left view of a binary tree iteratively
# node class
class node:
    def __init__(self, element):
        self.data = element
        self.hd = -1
        self.left = None
        self.right = None

# BFS itertative using queue for left view
def left_view_iterative(root):
    if root is None:
        return

    # creating a Queue for storing node for level wise traversal
    Q = list()
    Q.append(root)
    level = 0
    max_level = 0
    print("Left view of the binary tree is : ")
    while len(Q):
        # store the current size of the Q
        count = len(Q)
        level += 1
        while count != 0:
            # pop the first node from the queue
            NODE = Q[0]
            del Q[0]
            if level > max_level:
                print(NODE.data, end=" ")
                max_level = level

            # push the left child on queue
            if NODE.left is not None:
                Q.append(NODE.left)

            # push the right child on queue
            if NODE.right is not None:
                Q.append(NODE.right)
            count -= 1
    print()

head = node(1)
head.left = node(2)
head.right = node(3)
head.left.left = node(4)
head.left.right = node(5)
head.right.right = node(6)
head.left.left.right = node(7)
head.right.right.left = node(8)
head.left.left.right.left = node(9)
head.left.left.right.left.left = node(10)
head.right.right.left.right = node(11)
left_view_iterative(head)