tvl-depot/scratch/deepmind/part_two/permutation-palindrome.py
William Carroll 93d654df77 Solve InterviewCake permutation-palindrome problem
Write a predicate to test whether any permutation of an input string is a
palindrome.
2020-03-01 22:32:24 +00:00

37 lines
1 KiB
Python

import unittest
from collections import Counter
def has_palindrome_permutation(xs):
vs = Counter(xs).values()
return len([v for v in vs if v % 2 == 1]) in {0, 1}
# Tests
class Test(unittest.TestCase):
def test_permutation_with_odd_number_of_chars(self):
result = has_palindrome_permutation('aabcbcd')
self.assertTrue(result)
def test_permutation_with_even_number_of_chars(self):
result = has_palindrome_permutation('aabccbdd')
self.assertTrue(result)
def test_no_permutation_with_odd_number_of_chars(self):
result = has_palindrome_permutation('aabcd')
self.assertFalse(result)
def test_no_permutation_with_even_number_of_chars(self):
result = has_palindrome_permutation('aabbcd')
self.assertFalse(result)
def test_empty_string(self):
result = has_palindrome_permutation('')
self.assertTrue(result)
def test_one_character_string(self):
result = has_palindrome_permutation('a')
self.assertTrue(result)
unittest.main(verbosity=2)