题解 | 识别有效的IP地址和掩码并进行分类统计

import sys

# # 判断子网掩码有效性
def valadd(add):
    flag = 1 #当前没有遇到过0
    flag1 = 0 #是否遇到过1
    for n in add:
        k = 128
        while k:
            if n & k and flag:#没有遇到0
                flag1 = 1
                pass
            elif n & k ==0 and flag:#第一次遇到0
                flag = 0
            elif n & k and not flag:#遇到1之前遇到过0
                return 0
            elif n & k == 0 and not flag:
                pass
            k = k >> 1
    if flag1 and not flag:
        return 1
    else:
        return 0


# k = valadd([42])
## 判断ip属于哪一类，是否私有（必须输入有效ip）
def judip(ip):
    res = ['a',0]
    if ip[0]>=1 and ip[0]<=127:
        res[0]='A'
        if ip[0]==10:
            res[1]=1
    elif ip[0]>=128 and ip[0]<=191:
        res[0]='B'
        if ip[0]==172 and (ip[1]>=16 and ip[1]<=31):
            res[1]=1
    elif ip[0]>=192 and ip[0]<=223:
        res[0]='C'
        if ip[0]==192 and (ip[1]==168):
            res[1]=1
    elif ip[0]>=224 and ip[0]<=239:
        res[0]='D'
        res[1]=0
    elif ip[0]>=240 and ip[0]<=255:
        res[0]='E'
        res[1]=0
    return res

numA,numB,numC,numD,numE,numerr,numpri=0,0,0,0,0,0,0
for line in sys.stdin:  
    total = line.strip().split("~")
    ip = total[0].split(".")
    add = total[1].split(".")
    ip = [int(x) for x in ip if x]
    add = [int(x) for x in add if x]
    lenip,lenadd = len(ip),len(add)
    # print(valadd(add))
    if ip[0]==0 or ip[0]==127:
        continue
    elif lenip==4 and lenadd==4 and valadd(add):
        lei = judip(ip)
        if lei[0]=='A':
            numA+=1
        elif lei[0]=='B':
            numB+=1
        elif lei[0]=='C':
            numC+=1
        elif lei[0]=='D':
            numD+=1
        elif lei[0]=='E':
            numE+=1
        if lei[1] == 1:
            numpri+=1
    else:
        numerr+=1
print(numA,numB,numC,numD,numE,numerr,numpri)