【十二题解】 | #识别有效的IP地址和掩码并进行分类统计#暴力破解

先把所有字符读入，再判断ip和子网是否符合规则

#include<stdio.h>

int ip_judge(charip, intp){

int one[4];
int i=0;
memset(one, -1, sizeof(int)*4);
for(;ip[*p]!='~';(*p)++){
    int number_exist =0;
    int number = 0;
    for(;ip[*p] != '.' && ip[*p] != '~';(*p)++){
        int aa = *p;
        char bb = ip[*p];
        number_exist = 1;
        number=number*10+(ip[*p]-48);
    }
    if(number_exist){
        one[i]=number;
    }
    i++;
    if(ip[*p] == '~'){
        (*p)--;
    }
}
(*p)++;
int kk = *p;
int ans=0;
if(one[0]==0 || one[0]==127)return 1000;
if(one[0]==-1||one[1]==-1||one[2]==-1||one[3]==-1||one[0]>255||one[1]>255||one[2]>255||one[3]>255)return 0;
if(one[0]>=1 && one[0]<=126)ans+=1;
if(one[0]>=128 && one[0]<=191)ans+=2;
if(one[0]>=192 && one[0]<=223)ans+=3;
if(one[0]>=224 && one[0]<=239)ans+=4;
if(one[0]>=240 && one[0]<=255)ans+=5;
if(one[0]==10)ans+=10;
if(one[0]==172 && one[1]>=16 && one[1]<=31)ans+=10;
if(one[0]==192 && one[1]==168)ans+=10;
return ans;

}

int sub_judge(charip, intp){

char two[33];
memset(two, -1, sizeof(char)*33);
int i=0;
for(;ip[*p]!='\n';(*p)++)
{
    int aaaaa=*p;
    char bbbbb=ip[*p];
    int number_exist =0;
    int number = 0;
    for(;ip[*p] != '.' && ip[*p] != '\n';(*p)++){
        number_exist = 1;
        number=number*10+(ip[*p]-48);
    }
    if(number_exist){
        int times=i*8+8;
        int x=128;
        for(int first=i*8; first<times; first++){
            int bit=x & number;
            if(bit==x){
              two[first]='1';
            }
            else{
                two[first]='0';
            }
            x>>=1;
        }
    }
    i++;
    if(ip[*p] == '\n'){
        (*p)--;
    }
}
(*p)++;
int aaaa=*p;
int all_zero=1;
int all_one=1;
for(int j=0; j<32; j++){
    if(two[j]=='1')all_zero=0;
    if(two[j]=='0')all_one=0;
    if(j!=0 && j!=31 && two[j]=='1' && two[j-1]=='0' && two[j+1]=='0')return 0;
    if(j!=0 && j!=31 && two[j]=='0' && two[j+1]=='1')return 0;
    if(two[0]=='0')return 0;
    if(two[31]=='1')return 0;
    if(j==31 && two[j]=='1' && two[j-1]=='0')return 0;
}
if(all_zero || all_one)return 0;
return 1;

}

int main(){

char ip[13000];
int a=0, b=0, c=0, d=0, e=0, error=0, pri=0;
memset(ip, -1, sizeof(char)*1000);
char *loc=ip;
while(~scanf("%c", loc))loc++;
int lenth=(loc-ip)/sizeof(char);
int i;
int *p=&i;
for(i=0; i<lenth;){
    int one=ip_judge(ip, p);
    int two=sub_judge(ip, p);
    if(one && two){
        if(one!=1000){
            int x = one%10;
            one /=10;
            if(x==1)a++;
            if(x==2)b++;
            if(x==3)c++;
            if(x==4)d++;
            if(x==5)e++;
            if(one==1)pri++;
        }
    }
    else if(one!=1000){
        error++;
    }
}
printf("%d %d %d %d %d %d %d", a, b, c, d, e, error, pri);
return 0;

}