gcd works with negatives numbers and it is now tested

This commit is contained in:
Lafrite 2014-02-22 10:12:05 +01:00
parent ceab817c28
commit c3a6628ae3
2 changed files with 62 additions and 9 deletions

View File

@ -10,19 +10,30 @@ def gcd(a, b):
:returns: the gcd :returns: the gcd
""" """
if a > b: pos_a, _a = (a >= 0), abs(a)
c = a % b pos_b, _b = (b >= 0), abs(b)
gcd_sgn = (-1 + 2*(pos_a or pos_b))
if _a > _b:
c = _a % _b
else: else:
c = b % a c = _b % _a
if c == 0: if c == 0:
return min(a,b) return gcd_sgn * min(_a,_b)
elif a == 1: elif _a == 1:
return b return gcd_sgn * _b
elif b == 1: elif _b == 1:
return a return gcd_sgn * _a
else: else:
return gcd(min(a,b), c) return gcd_sgn * gcd(min(_a,_b), c)
if __name__ == '__main__':
print(gcd(3, 15))
print(gcd(3, 15))
print(gcd(-15, -3))
print(gcd(-3, -12))
# ----------------------------- # -----------------------------

42
test/test_arthmetic.py Normal file
View File

@ -0,0 +1,42 @@
#!/usr/bin/env python
# encoding: utf-8
import unittest
from pymath import arithmetic
class TestArithmetic(unittest.TestCase):
"""Testing functions from pymath.arithmetic"""
def test_gcd_commu(self):
self.assertEqual(arithmetic.gcd(3, 15), arithmetic.gcd(15,3))
def test_gcd1(self):
self.assertEqual(arithmetic.gcd(3, 15), 3)
def test_gcd2(self):
self.assertEqual(arithmetic.gcd(14, 21), 7)
def test_gcd_prem(self):
self.assertEqual(arithmetic.gcd(14, 19), 1)
def test_gcd_neg(self):
self.assertEqual(arithmetic.gcd(3, -15), 3)
self.assertEqual(arithmetic.gcd(-3, -15), -3)
if __name__ == '__main__':
unittest.main()
# -----------------------------
# Reglages pour 'vim'
# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
# cursor: 16 del