题解 | #识别有效的IP地址和掩码并进行分类统计#

#include <iostream>
#include<string>
#include<vector>
using namespace std;

//分割
//判断
//输出

vector<string> split(string str, const char c) {
    vector<string> vstr;
    int posStart = 0;
    while (posStart < str.length()) {
        int posEnd;
        for (posEnd = posStart; str[posEnd] != c && posEnd < str.length(); posEnd++);
        vstr.push_back(str.substr(posStart, posEnd - posStart));
        posStart = posEnd + 1;
    }
    return vstr;
}

unsigned long valueIP(int x0, int x1, int x2, int x3) {
    unsigned long value_IP = x0 * 255 * 255 * 255 + x1 * 255 * 255 + x2 * 255 + x3;
    return value_IP;

}

char typeIP(string str) {
    vector<string> vstr = split(str, '.');
    if (vstr.size() == 4) {
        int num0 = atoi(vstr[0].c_str());
        int num1 = atoi(vstr[1].c_str());
        int num2 = atoi(vstr[2].c_str());
        int num3 = atoi(vstr[3].c_str());
        if ((num0 > 0 && num0 <= 255) && (num1 >= 0 && num1 <= 255) && (num2 >= 0 &&
                num2 <= 255) && (num3 >= 0 && num3 <= 255)) {
            unsigned long value = valueIP(num0, num1, num2, num3);
            if ((value >= valueIP(1, 0, 0, 0)) && value <= valueIP(126, 255, 255, 255)) {
                if ((value >= valueIP(10, 0, 0, 0)) && value <= valueIP(10, 255, 255, 255)) {
                    return 'a';
                }
                return 'A';
            }
            if ((value >= valueIP(128, 0, 0, 0)) && value <= valueIP(191, 255, 255, 255)) {
                if ((value >= valueIP(172, 16, 0, 0)) && value <= valueIP(172, 31, 255, 255)) {
                    return 'b';
                }
                return 'B';
            }
            if ((value >= valueIP(192, 0, 0, 0)) && value <= valueIP(223, 255, 255, 255)) {
                if ((value >= valueIP(192, 168, 0, 0)) &&
                        value <= valueIP(192, 168, 255, 255)) {
                    return 'c';
                }
                return 'C';
            }
            if ((value >= valueIP(224, 0, 0, 0)) && value <= valueIP(239, 255, 255, 255)) {
                
                return 'D';
            }
            if ((value >= valueIP(240, 0, 0, 0)) && value <= valueIP(255, 255, 255, 255)) {
                
                return 'E';
            }
            return 'X';
        }
        return 'X';
    }
    return 'X';
}
bool isOk(int num){
    int a=num-128;
    if(a!=0){
        a-=64;
        if(a!=0){
            a-=32;
            if(a!=0){
                a-=16;
                if(a!=0){
                    a-=8;
                    if(a!=0){
                        a-=4;
                        if(a!=0){
                            a-=2;
                            if(a!=0){
                                a-=1;
                                if(a!=0){
                                    return  false;
                                }else{
                                    return  true;
                                }
                            }else{
                                return  true;
                            }
                        }else{
                            return  true;
                        }
                    }else{
                        return  true;
                    }
                }else{
                    return  true;
                }
            }else{
                return  true;
            }
        }else{
            return  true;
        }
    }else{
        return true;
    }
}

bool isSubNetMask(string str){
    vector<string> vstr = split(str, '.');
    if (vstr.size() == 4) {
        int num0 = atoi(vstr[0].c_str());
        int num1 = atoi(vstr[1].c_str());
        int num2 = atoi(vstr[2].c_str());
        int num3 = atoi(vstr[3].c_str());
        // 1 2 4 8      16 32 64 128
        if ((num0 > 0 && num0 <= 255) && (num1 >= 0 && num1 <= 255) && (num2 >= 0 &&
                num2 <= 255) && (num3 >= 0 && num3 <= 255)) {
            if(num0==255){
                if(num1==255){
                    if(num2==255){
                        if(num3==255){
                            return  false;
                        }else{
                            if(isOk(num3)||num3==0){
                                return true;
                            }
                        }
                        return  false;
                    }else{
                        if(num3==0){
                            if(isOk(num2)||num2==0){
                                return true;
                            }
                        }
                        return  false;
                    }
                }else{
                    if(num2==0&&num3==0){
                        if(isOk(num1)||num1==0){
                            return true;
                        }
                    }
                    return  false;
                }
            }else{
                if(num1==0&&num2==0&&num3==0){
                    if(isOk(num0)){
                        return true;
                    }
                }
                return  false;
            }
        }
    }
    return false;
}

int main() {
    string str;
    int numA=0,numB=0,numC=0,numD=0,numE=0,numError=0,numPrivate=0;
    int j=1;
    while (getline(cin, str)) { 
        vector<string> vStrs=split(str, '~');
        if(vStrs.size()==2){
            //cout<<j<<" -- ";
            if(isSubNetMask(vStrs[1])){
                switch(typeIP(vStrs[0])){
                    case 'A':
                        numA++;
                        //cout<<vStrs[0]<<" : "<<'A'<<" "<<numA<<endl;
                        break;
                    case 'a':
                        numA++;
                        numPrivate++;
                        //cout<<vStrs[0]<<" : "<<'a'<<" "<<numA<<" "<<numPrivate<<endl;
                        break;
                    case 'B':
                        numB++;
                        //cout<<vStrs[0]<<" : "<<'B'<<" "<<numB<<endl;
                        break;
                    case 'b':
                        numB++;
                        numPrivate++;
                        //cout<<vStrs[0]<<" : "<<'b'<<" "<<numB<<" "<<numPrivate<<endl;
                        break;
                    case 'C':
                        numC++;
                        //cout<<vStrs[0]<<" : "<<'C'<<" "<<numC<<endl;
                        break;
                    case 'c':
                        numC++;
                        numPrivate++;
                        //cout<<vStrs[0]<<" : "<<'c'<<" "<<numC<<" "<<numPrivate<<endl;
                        break;
                    case 'D':
                        numD++;
                        //cout<<vStrs[0]<<" : "<<'D'<<" "<<numD<<endl;
                        break;
                    case 'E':
                        numE++;
                        //cout<<vStrs[0]<<" : "<<'E'<<" "<<numE<<endl;
                        break;
                    case 'X':
                        //cout<<vStrs[0]<<" : "<<"X-numError"<<endl;
                        break;
                }
            }else{
                if(typeIP(vStrs[0])!='X'){
                    numError++;
                    //cout<<vStrs[1]<<" :numError "<< numError<<endl;
                }
            }
            j++;
        }
    }
    //5 4 2 0 0 11 0
    cout<<numA<<' '<<numB<<' '<<numC<<' '<<numD<<' '<<numE<<' '<<numError<<' '<<numPrivate<<endl;
}