tvl-depot/users/wpcarro/scratch/data_structures_and_algorithms/permutation-palindrome.py

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from collections import Counter
import unittest
################################################################################
# Impl
################################################################################
# palindromifiable :: String -> Boolean
def has_palindrome_permutation(x):
bag = Counter(x)
odd_entries_ct = 0
for _, y in bag.items():
if y % 2 != 0:
odd_entries_ct += 1
return odd_entries_ct 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)