题解 | #判断两个IP是否属于同一子网#

大佬函数名掉了，补上

def int2bin(ipt):
    lst = list(map(int, ipt.split('.')))
    res = ''
    for i in lst:
        a = bin(i)[2:]
        b = '0' * (8 - len(a)) + str(a)
        res += b
    return res


def check_ip(ip):
    ip_lst = list(map(int, ip.split('.')))
    if len(ip_lst) != 4 or '' in ip_lst:
        return False
    for i in ip_lst:
        if not 0 <= i <= 255:
            return False
    return True


def check_mask(mask):
    if not check_ip(mask):
        return False
    res = int2bin(mask)
    if res.find('0') == res.rfind('1') + 1:
        return True
    return False


def check_subnet(ip, mask):
    ip_lst = list(map(int, ip.split('.')))
    mask_lst = list(map(int, mask.split('.')))
    subnet = []
    for i in range(4):
        subnet.append(ip_lst[i] & mask_lst[i])
    return subnet


while True:
    try:
        mask1 = input()
        ip1 = input()
        ip2 = input()
        if check_mask(mask1) and check_ip(ip1) and check_ip(ip2):
            if check_subnet(ip1, mask1) == check_subnet(ip2, mask1):
                print('0')
            else:
                print('2')
        else:
            print('1')
    except:
        break