BTree | Python Fiddle

class BTree:

def __init__(self):
    self.root = None
    self.strategy = BTreeInsertStrategry()

def Insert(self, v):
    node = Node(v)
    if self.root == None:
      self.root = node
    else:
  	 self.root.AddChild(node, self.strategy)

def balanceTree(self, node):
   rh = node.GetRightHeight()
   lh = node.GetLeftHeight()
   print("rh:" + str(rh))
   print("lh:" + str(lh))
   if rh > lh + 1:
     if node == self.root:
      self.root = node.right
     node.RotateLeft()
     print "left rotated:" + str(node.value)
   elif lh > rh + 1:
    if node == self.root:
      self.root = node.left

node.RotateRight()
    print "right rotated:" + str(node.value)

class BTreeInsertStrategry:

def InsertLeft(self, root, node):
    if root.value > node.value:
      return 1
    else:
      return 0;

class PreOrderPrinter:

def printNode(self, root):
    if root != None:
      print(root.value)

self.printNode(root.left)

self.printNode(root.right)

class AvlTreeBalancer:

def balanceTree(self, node):
    rh = node.GetRightHeight()
    lh = node.GetLeftHeight()
    print("rh:" + str(rh))
    print("lh:" + str(lh))
    if rh > lh + 1:
      node.RotateLeft()
      print "left rotated:" + str(node.value)
    elif lh > rh + 1:
      node.RotateRight()
      print "right rotated:" + str(node.value)

class Node:

def __init__(self, v):
    self.left = None
    self.right = None
    self.root = None
    self.value = v
    self.height = 0

def GetRightHeight(self):
    if self.right == None:
      return 0
    else:
      return 1 + self.right.height

def GetLeftHeight(self):
    if self.left == None:
      return 0
    else:
      return 1 + self.left.height

def AddChild(self, node, strategy):

if strategy.InsertLeft(self, node) == 1:
      if self.left == None:
        node.root = self
        self.left = node
      else:
        self.left.AddChild(node, strategy)
    else:
      if self.right == None:
        node.root = self
        self.right = node
      else:
        self.right.AddChild(node, strategy)

self.UpdateHeights()

def IsHeavyLeft():
    return GetLeftHeight() > GetRightHeight()

def IsHeavyRIght():
    return GetRightHeight() < GetLeftHeight()

def UpdateHeights(self):
    leftHeight = 0
    rightHeight = 0
    if self.left != None:
      self.left.UpdateHeights()

leftHeight = 1 + self.left.height

if self.right != None:
      self.right.UpdateHeights()
      rightHeight = 1 + self.right.height

self.height = max(leftHeight, rightHeight)

def RotateLeft(self):
    handshakeNode = self.right.left
    self.right.left = self
    self.right = handshakeNode

def RotateRight(self):
    handshakeNode = self.left.right
    self.left.right = self
    self.left = handshakeNode

data = [1,2,3]
printer = PreOrderPrinter()

btree = BTree()
balancer = AvlTreeBalancer()
for v in data:
    print("********************************************")
    btree.Insert(v)
    printer.printNode(btree.root)
    btree.balanceTree(btree.root)
    print("--------------------------------------------")
    printer.printNode(btree.root)
    print("++++++++++++++++++++++++++++++++++++++++++++")

print "The End"

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