Tree Top View on HackerRank.com

treetopview_hackerrank.py

import queue

class NodeWrap:
    def __init__(self, node, hd):
        self.node = node  
        self.hd = hd 

def topView(root):
    d = {}
    q = queue.Queue()
    q.put(NodeWrap(root, 0))
    while not q.empty():
        node_wrap = q.get()
        node = node_wrap.node
        current_hd = node_wrap.hd
        if d.get(current_hd) is None:
            d[current_hd] = node
            print(node.info, end=" ")
        if node.left is not None:
            q.put(NodeWrap(node.left, current_hd - 1))
        if node.right is not None:
            q.put(NodeWrap(node.right, current_hd + 1))