balanced-tree.py

class Node:
	"""
	>>> Node(1).append(
	...  Node(2)).append(
	...    Node(3)).append(
	...      Node(4)).append(
	...        Node(5)).append(
	...          Node(6)).append(
	...            Node(7)).append(
	...              Node(8)).pprint()
	 1
	  2
	   5
	   8
	  3
	   6
	  4
	   7
	>>>
	"""
	MAX = 3
	def __init__(self, value):
		self.value = value
		self.children = []
		
	def append(self, node):
		if len(self.children) < self.MAX:
			self.children.append(node)
		else:
			_, indx = min(zip(map(len, self.children),xrange(len(self.children))))
			self.children[indx].append(node)			
		return self
			
	def __len__(self):
		return len(self.children)
		
	def pprint(self, indent=0):
		print " " * indent, self.value
		for child in self.children:
			child.pprint(indent+1)

			
if __name__ == "__main__":
    import doctest
    doctest.testmod()