题解 | #判断两个IP是否属于同一子网#

测试狗平常不用&符都忘记了，无脑转换

注意坑：

1. 掩码要校验0-255和转换后前半分是1后半部分是0的情况
2. bin函数转换后取消0b并且左侧补0到8位
3. 注意if逻辑，他那个0,1,2还不按顺序描述 =================

下次更新使用&符号的做法

import re


def transfer_ip(ip):
    ip_list = [bin(int(x))[2:].rjust(8,'0') for x in ip.split('.')]
    return ''.join(ip_list)

def transfer_mask(mask):
    mask_list = [bin(int(x))[2:].rjust(8, '0') for x in mask.split('.') if 1 <= int(x) <= 255]
    return ''.join(mask_list)
    
    
def valid_ip(ip):
    ip_list = [int(x) for x in ip.split('.') if 0 <= int(x) <= 255]
    if len(ip_list) == 4:
        return True
    return False

def valid_mask(mask):
    mask_list = [bin(int(x))[2:].rjust(8, '0') for x in mask.split('.') if 0 <= int(x) <= 255]
    mask_str = ''.join(mask_list)
    pattern = re.compile('^[1]{1,32}[0]{1,32}$')
    if pattern.search(mask_str) and len(mask_list) == 4:
        return True
    return False

def get_ip_and_mask(ip_str, mask_str):
    and_ip = ''
    for x,y in zip(ip_str, mask_str):
        if x == '1' and y == '1':
            and_ip += '1'
        else:
            and_ip += '0'
    return and_ip

while True:
    try:
        mask, ip1, ip2 = input(),input(),input()
        if valid_ip(ip1) and valid_ip(ip2) and valid_mask(mask):
            t_ip1, t_ip2, t_mask = transfer_ip(ip1), transfer_ip(ip2), transfer_mask(mask)
            and_ip1 = get_ip_and_mask(t_ip1, t_mask)
            and_ip2 = get_ip_and_mask(t_ip2, t_mask)
            if and_ip1 == and_ip2:
                print(0)
            else:
                print(2)
        else:
            print(1)
    except EOFError:
        break