This notebook was prepared by Donne Martin. Source and license info is on GitHub.

# Solution Notebook¶

## Constraints¶

• Is this a binary tree?
• Yes
• Can we assume we already have a Node class with an insert method?
• Yes
• Can we assume this fits memory?
• Yes

## Test Cases¶

• 5 -> 1
• 5, 2, 8, 1, 3 -> 3

## Algorithm¶

We'll use a recursive algorithm.

• If the current node is None, return 0
• Else, return 1 + the maximum height of the left or right children

Complexity:

• Time: O(n)
• Space: O(h), where h is the height of the tree

## Code¶

In [1]:
%run ../bst/bst.py
In [2]:
class BstHeight(Bst):

def height(self, node):
if node is None:
return 0
return 1 + max(self.height(node.left),
self.height(node.right))

## Unit Test¶

In [3]:
%%writefile test_height.py
import unittest

class TestHeight(unittest.TestCase):

def test_height(self):
bst = BstHeight(Node(5))
self.assertEqual(bst.height(bst.root), 1)
bst.insert(2)
bst.insert(8)
bst.insert(1)
bst.insert(3)
self.assertEqual(bst.height(bst.root), 3)

print('Success: test_height')

def main():
test = TestHeight()
test.test_height()

if __name__ == '__main__':
main()
Overwriting test_height.py
In [4]:
%run -i test_height.py
Success: test_height