Prints a given tree in levels, using BFS - using Python

print_levels_tree.py

# Print tree by levels - using BFS
# The idea behind it is to use BFS and keep a level marker integer which marks the end the last node of the level. This is similar to Naresh's sentinel approach, but without the need of inserting a sentinel inside the queue, since this is accomplished by the level marker.
# Time complexity of O(n)
# Space complexity: O(2^tree_height)

from collections import deque

class Node:
    def __init__(self, data, left=None, right=None):
        self.data = data
        self.left = left
        self.right = right
        
def print_levels_tree(root: Node):
    q = deque()
    q.append(root)
    level, level_marker = 0, 1
    while q:
        if (level_marker == 0):
            level, level_marker = level + 1, len(q)
            print("", end = '\n')
        level_marker -= 1
        
        node = q.popleft()
        
        if (node is None):
            continue
        
        print(node.data, "\t", end = '')
        
        q.append(node.left)
        q.append(node.right)

        
# Some examples
tree = Node(19, Node(7, Node(3), Node(11)), Node(19)) 
print_levels_tree(tree)

left = Node(7, Node(3, Node(2), Node(5)), Node(11, None, Node(17, Node(13))))
tree = Node(19, left, Node(43))
print_levels_tree(tree)

left = Node(7, Node(3, Node(2), Node(5)), Node(11, None, Node(17, Node(13))))
right = Node(43, Node(23, None, Node(37, Node(29, None, Node(31)), Node(41))), Node(47, None, Node(53)) )
tree = Node(19, left, right)
print_levels_tree(tree)