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"""

An auto-balanced binary tree!

"""

import math

import random

class my_queue:

def __init__(self):

self.data = []

self.head = 0

self.tail = 0

def isEmpty(self):

return self.head == self.tail

def push(self, data):

self.data.append(data)

self.tail = self.tail + 1

def pop(self):

ret = self.data[self.head]

self.head = self.head + 1

return ret

def count(self):

return self.tail - self.head

def print(self):

print(self.data)

print("**************")

print(self.data[self.head : self.tail])

class my_node:

def __init__(self, data):

self.data = data

self.left = None

self.right = None

self.height = 1

def getdata(self):

return self.data

def getleft(self):

return self.left

def getright(self):

return self.right

def getheight(self):

return self.height

def setdata(self, data):

self.data = data

return

def setleft(self, node):

self.left = node

return

def setright(self, node):

self.right = node

return

def setheight(self, height):

self.height = height

return

def getheight(node):

if node is None:

return 0

return node.getheight()

def my_max(a, b):

if a > b:

return a

return b

def leftrotation(node):

r"""

A B

/ \ / \

B C Bl A

/ \ --> / / \

Bl Br UB Br C

UB = unbalanced node

"""

print("left rotation node:", node.getdata())

ret = node.getleft()

node.setleft(ret.getright())

ret.setright(node)

h1 = my_max(getheight(node.getright()), getheight(node.getleft())) + 1

node.setheight(h1)

h2 = my_max(getheight(ret.getright()), getheight(ret.getleft())) + 1

ret.setheight(h2)

return ret

def rightrotation(node):

"""

a mirror symmetry rotation of the leftrotation

"""

print("right rotation node:", node.getdata())

ret = node.getright()

node.setright(ret.getleft())

ret.setleft(node)

h1 = my_max(getheight(node.getright()), getheight(node.getleft())) + 1

node.setheight(h1)

h2 = my_max(getheight(ret.getright()), getheight(ret.getleft())) + 1

ret.setheight(h2)

return ret

def rlrotation(node):

r"""

A A Br

/ \ / \ / \

B C RR Br C LR B A

/ \ --> / \ --> / / \

Bl Br B UB Bl UB C

\ /

UB Bl

RR = rightrotation LR = leftrotation

"""

node.setleft(rightrotation(node.getleft()))

return leftrotation(node)

def lrrotation(node):

node.setright(leftrotation(node.getright()))

return rightrotation(node)

def insert_node(node, data):

if node is None:

return my_node(data)

if data < node.getdata():

node.setleft(insert_node(node.getleft(), data))

if (

getheight(node.getleft()) - getheight(node.getright()) == 2

): # an unbalance detected

if (

data < node.getleft().getdata()

): # new node is the left child of the left child

node = leftrotation(node)

else:

node = rlrotation(node) # new node is the right child of the left child

else:

node.setright(insert_node(node.getright(), data))

if getheight(node.getright()) - getheight(node.getleft()) == 2:

if data < node.getright().getdata():

node = lrrotation(node)

else:

node = rightrotation(node)

h1 = my_max(getheight(node.getright()), getheight(node.getleft())) + 1

node.setheight(h1)

return node

def getRightMost(root):

while root.getright() is not None:

root = root.getright()

return root.getdata()

def getLeftMost(root):

while root.getleft() is not None:

root = root.getleft()

return root.getdata()

def del_node(root, data):

if root.getdata() == data:

if root.getleft() is not None and root.getright() is not None:

temp_data = getLeftMost(root.getright())

root.setdata(temp_data)

root.setright(del_node(root.getright(), temp_data))

elif root.getleft() is not None:

root = root.getleft()

else:

root = root.getright()

elif root.getdata() > data:

if root.getleft() is None:

print("No such data")

return root

else:

root.setleft(del_node(root.getleft(), data))

elif root.getdata() < data:

if root.getright() is None:

return root

else:

root.setright(del_node(root.getright(), data))

if root is None:

return root

if getheight(root.getright()) - getheight(root.getleft()) == 2:

if getheight(root.getright().getright()) > getheight(root.getright().getleft()):

root = rightrotation(root)

else:

root = lrrotation(root)

elif getheight(root.getright()) - getheight(root.getleft()) == -2:

if getheight(root.getleft().getleft()) > getheight(root.getleft().getright()):

root = leftrotation(root)

else:

root = rlrotation(root)

height = my_max(getheight(root.getright()), getheight(root.getleft())) + 1

root.setheight(height)

return root

class AVLtree:

def __init__(self):

self.root = None

def getheight(self):

# print("yyy")

return getheight(self.root)

def insert(self, data):

print("insert:" + str(data))

self.root = insert_node(self.root, data)

def del_node(self, data):

print("delete:" + str(data))

if self.root is None:

print("Tree is empty!")

return

self.root = del_node(self.root, data)

def traversale(self): # a level traversale, gives a more intuitive look on the tree

q = my_queue()

q.push(self.root)

layer = self.getheight()

if layer == 0:

return

cnt = 0

while not q.isEmpty():

node = q.pop()

space = " " * int(math.pow(2, layer - 1))

print(space, end="")

if node is None:

print("*", end="")

q.push(None)

else:

print(node.getdata(), end="")

q.push(node.getleft())

q.push(node.getright())

print(space, end="")

cnt = cnt + 1

for i in range(100):

if cnt == math.pow(2, i) - 1:

layer = layer - 1

if layer == 0:

print()

print("*************************************")

return

print()

break

print()

print("*************************************")

return

def test(self):

getheight(None)

print("****")

self.getheight()

if __name__ == "__main__":

t = AVLtree()

t.traversale()

l = list(range(10))

random.shuffle(l)

for i in l:

t.insert(i)

t.traversale()

random.shuffle(l)

for i in l:

t.del_node(i)

t.traversale()

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