associated to my blog: http://matsub.hatenablog.com/entry/2014/12/08/190018

gcd.py

# famous
def gcd(a, b):
    if b:
        return gcd(b, a%b)
    return a

# non-recursive
def Gcd(a, b):
    while b:
        a, b = b, a%b
    return a

# short
def GCD(a, b):
    return gcd(b, a%b) if b else a

# Z-Combinator
Z = lambda f: (lambda x: f(lambda y: x(x)(y)))(lambda x: f(lambda y: x(x)(y)))
Zgcd = lambda f: (lambda a: (lambda b: f(b)(a%b) if b else a))

'''
>>> gcd(12, 64)
4
>>> GCD(24, 64)
8
>>> Z(Zgcd)(12)(64)
4
>>> Z(Zgcd)(24)(64)
8
'''