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1.2. check permutation pythonic changes 

use of counter and *strings for tuples
This commit is contained in:
anebz 2019-03-28 19:00:52 +01:00
parent 78c1fd4eef
commit e19eb712f1
1 changed files with 36 additions and 11 deletions
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47
Chapter 1 Arrays and strings/1.2. check_permutation.py
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@ -1,10 +1,12 @@
import unittest import unittest
from time import time
from collections import Counter
def check_permutation(s1, s2): def check_permutation(s1, s2):
if len(s1) != len(s2): if len(s1) != len(s2):
return False return False
checker = dict()
checker = dict()
for char in s1: for char in s1:
ascii_val = ord(char) ascii_val = ord(char)
if ascii_val not in checker: if ascii_val not in checker:
@ -17,29 +19,52 @@ def check_permutation(s1, s2):
if ascii_val not in checker: if ascii_val not in checker:
return False return False
checker[ascii_val] -= 1 checker[ascii_val] -= 1
if checker[ascii_val] == 0:
del checker[ascii_val]
if checker[ascii_val] < 0: if checker[ascii_val] < 0:
return False return False
if checker == {}: return True
return True
else: def check_permutation_pythonic(s1, s2):
if len(s1) != len(s2):
return False return False
if len(s1) <= 1:
return True
counter = Counter()
for char in s1:
counter[char] += 1
for char in s2:
if counter[char] == 0:
return False
counter[char] -= 1
return True
class Test(unittest.TestCase): class Test(unittest.TestCase):
dataT = [('abcd', 'dbca'), ('dfgh', 'dfgh'), ('', '')] dataT = [('abcd', 'dbca'), ('dfgh', 'dhgf'), ('', '')]
dataF = [('aane', 'anee'), ('ab', 'ca'), ('ane', 'aane')] dataF = [('aane', 'anee'), ('ab', 'ca'), ('ane', 'aane')]
def test(self): def test(self):
# true check # true check
for test_string in self.dataT: for test_string in self.dataT:
s1, s2 = test_string start = time()
res = check_permutation(s1, s2) res = check_permutation(*test_string)
self.assertTrue(res) self.assertTrue(res)
print(f"{time() - start}s")
start = time()
res = check_permutation_pythonic(*test_string)
self.assertTrue(res)
print(f"{time() - start}s")
# false check # false check
for test_string in self.dataF: for test_string in self.dataF:
s1, s2 = test_string start = time()
res = check_permutation(s1, s2) res = check_permutation(*test_string)
self.assertFalse(res)
print(f"{time() - start}s")
start = time()
res = check_permutation_pythonic(*test_string)
print(f"{time() - start}s")
self.assertFalse(res) self.assertFalse(res)
if __name__ == "__main__": if __name__ == "__main__":