题解 | #判断两个IP是否属于同一子网#

while True:
    try:
        string1=input()
        string2=input()
        string3=input()
        Netmask = string1.split(".")
        Ip1 = string2.split(".")
        Ip2 = string3.split(".")
        ans=-1
        for i in range(4):
            while i<4:
                if i == 3 :
                    break
                elif (int(Netmask[i])<255 and int(Netmask[i+1]) != 0) or int(Netmask[i])>255 or int(Netmask[i])<0 :
                    ans = 1
                    break
                else:
                    break
            while int(Ip1[i]) < 0 or int(Ip1[i]) >=255 or int(Ip2[i]) <0 or int(Ip2[i]) >=255: 
                ans = 1
                break
            if ans == -1 or ans == 0:
                mask = int(Netmask[i])
                ip1 = int(Ip1[i])
                ip2 = int(Ip2[i])
                #print(mask)
                Ip1[i] = mask and ip1
                Ip2[i] = mask and ip2
                if Ip1[i] == Ip2[i]:
                    ans = 0
                else:
                    ans = 2
        print(ans)
    except:
        break