# Height of BSTby Isai Damier, Android Engineer @ Google

```  #=====================================================================
# Author: Isai Damier
# Title: Height
# Project: geekviewpoint
# Package: algorithms
#
# Time Complexity of Solution:
#   Best = Average = Worst = O(n).
#
# Description: Calculate the height of the given tree. This
#    method returns the size of the longest path from the self.root
#    to a leaf.
#
# Alternate Algorithm: If built-in function is acceptable,
#    then the recursive portion of the algorithm may be as
#    below:
#     def height(self, n):
#      if n is None:
#        return 0
#      return 1 + max(height(n.left), height(n.right))
#
#=====================================================================

class BST( object ):

def __init__( self ):
self.root = None

def getRoot( self ):
return self.root

def height( self ):
return self._height( self.root )

def _height( self, n ):
if n is None:
return 0
l = self._height( n.left )
r = self._height( n.right )
return 1 + ( l if l > r else r ) # highest subtree plus self
```
```import unittest
from algorithms.BST import BST
from cStringIO import StringIO
import sys
class Test( unittest.TestCase ):
#===================================================================
# Test of height method, of class BST.
#===================================================================
def testHeight( self ):
bst = BST()

treeTape = [200, 100, 300, 50, 150, 250, 350, 25, 75, 125,
175, 225, 275, 325, 375, 35, 212, 312, 400]
self.assertEquals( 0, bst.height() )
# set expectation
expected = 5 # draw the tree on paper