最大公约数

while True:
    try:
        n,m=map(int,input().strip().split(' '))
        #print(n,m)
        min_num=min(n,m)
        re=0
        for i in range(1,min_num+1):
            if n%i==0 and m%i==0:
                if i>re:
                    re=i
        print(re)
    except:
        break


while True:
    try:
        n,m=map(int,input().strip().split(' '))
        #print(n,m)
        min_num=min(n,m)
        max_num=max(n,m)
        while min_num!=0:
            temp=max_num%min_num
            max_num=min_num
            min_num=temp
        print(max_num)
    except:
        break

def gcd(a, b):
    if a < b:
        a, b = b, a

    while b != 0:
        temp = a % b
        a = b
        b = temp

    return a

while True:
    try:
        a, b = map(int, input().split())
        print(gcd(a, b))
    except:
        break

本来准备使用math库的，没想到被ban了？？

from fractions import gcd
try:
    while 1:
        print gcd(*map(int, raw_input().split()))
except:
    pass