U Suck at coding 2012-02-28

tree.py

#!/usr/bin/python

class Node(object):
    left = None
    right = None
    value = None
  
    def __init__(self, val):
        self.value = val

class Tree(object):
    root = None

    def __init__(self):
        root = Node(None)

def compare(a, b):
    """ Assuming a and b are both Node objects (or None), compare them. """
    if a and b:
        # Both a and b are actual objects.
        # Compare their values and recursively their children.
        return a.value == b.value and compare(a.left, b.left) and compare(a.right, b.right)
    else:
        # Both a and b should be None in order to be 'equal'.
        return a == b

def build_tree():
    t = Tree()
    t.root = Node("A")
    t.root.left = Node("D")
    t.root.right = Node("C")
    t.root.left.left = Node("B")
    return t

def main():
    # 2 identical trees.    
    t1 = build_tree()
    t2 = build_tree()
    
    # Random tree.
    t3 = Tree()
    t3.value = "D"
    t3.right = Node("A")
    
    assert compare(t1.root, t2.root)
    assert not compare(t1.root, t3.root)
    
if __name__ == '__main__':
    main()