3.8_greatest_common_divisor_欧几里得算法_最大公约数 (gcd)

def gcd(a, b):
    if b == 0:
        return a
    else:
        return gcd(b, a % b)


def gcd2(a, b):

    while b > 0:
        r = a % b
        a, b = b, r

    return a