Hi, here's your problem today. This problem was recently asked by Apple:
You are given a tree, and your job is to print it level-by-level with linebreaks.
a / \ b c / \ / \ d e f g
The output should be
a bc defg
Here's a starting point:
from collections import deque class Node(object): def __init__(self, val): self.val = val self.left = None self.right = None def __str__(self): # Fill this in. tree = Node('a') tree.left = Node('b') tree.right = Node('c') tree.left.left = Node('d') tree.left.right = Node('e') tree.right.left = Node('f') tree.right.right = Node('g') print tree # a # bc # defg