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Copy pathbst_num_empty.py
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72 lines (55 loc) · 1.78 KB
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"""
Write a function num_empty returns returns the number of empty branches in a
tree. Function should count the total number of empty branches among the nodes
of the tree. A leaf node has two empty branches. In the case, if root is None,
it considered as a 1 empty branch
For example: the following tree has 10 empty branch (* is empty branch)
9 __
/ \\___
6 12
/ \\ / \
3 8 10 15
/ \\ / \\ / \\ / \
* * 7 * * * * 18
/ \\ / \
* * * *
empty_branch = 10
"""
import unittest
from algorithms.data_structures.bst import BST
def num_empty(root):
if root is None:
return 1
elif root.left is None and root.right:
return 1 + num_empty(root.right)
elif root.right is None and root.left:
return 1 + num_empty(root.left)
else:
return num_empty(root.left) + num_empty(root.right)
"""
The tree is created for testing:
9
/ \
6 12
/ \\ / \
3 8 10 15
/ \
7 18
num_empty = 10
"""
class TestSuite(unittest.TestCase):
def setUp(self):
self.tree = BST()
self.tree.insert(9)
self.tree.insert(6)
self.tree.insert(12)
self.tree.insert(3)
self.tree.insert(8)
self.tree.insert(10)
self.tree.insert(15)
self.tree.insert(7)
self.tree.insert(18)
def test_num_empty(self):
self.assertEqual(10, num_empty(self.tree.root))
if __name__ == "__main__":
unittest.main()