简单解法

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

bool ismask(int a,int b,int c,int d);
bool isip(int a,int b,int c,int d);

int main(){
    int a,b,c,d;
    char ch;
    while(cin>>a>>ch>>b>>ch>>c>>ch>>d){
        int a1,b1,c1,d1;
        int a2,b2,c2,d2;
        cin >> a1 >> ch >> b1>>ch>>c1>>ch>>d1;
        cin>>a2>>ch>>b2>>ch>>c2>>ch>>d2;
        //cout << a1 << " " << b1 << " " << " " << c1 << " " << d1 << endl;
        //cout << a2 << " " << b2 << " " << " " << c2 << " " << d2 << endl;

        if(ismask(a,b,c,d)&&isip(a1,b1,c1,d1)&&isip(a2,b2,c2,d2)){
            vector<int> res1;
            vector<int> res2;
            //cout << (a1&a) << endl; 
            res1.push_back((a1&a));
            res1.push_back((b1&b));
            res1.push_back((c1&c));
            res1.push_back((d1&d));
            res2.push_back((a2&a));
            res2.push_back((b2&b));
            res2.push_back((c2&c));
            res2.push_back((d2&d));
            bool flag=true;
            for(int i=0;i<4;i++){
                if(res1[i]!=res2[i]){
                    flag=false;
                }
                //cout << res1[i] << " " << res2[i] << endl;
            }
            if(flag==true){
                cout << "0" << endl;
            }
            else{
                cout << "2" << endl;
            }
            res1.clear();
            res2.clear();
        }
        else{
            cout << "1" << endl;
        }

    }
    return 0; 
}

bool ismask(int a,int b,int c,int d){
    if((a==254||a==252||a==248||a==240||a==224||a==192||a==128)&&b==0&&c==0&&d==0){
        return true;
    }
    else if(a==255&&(b==254||b==252||b==248||b==240||b==224||b==192||b==128||b==0)&&c==0&&d==0){
        return true;
    }
    else if(a==255&&b==255&&(c==254||c==252||c==248||c==240||c==224||c==192||c==128||c==0)&&d==0){
        return true;
    }
    else if(a==255&&b==255&&c==255&&(d==254||d==252||d==248||d==240||d==224||d==192||d==128||d==0)){
        return true;
    }
    return false;
} 

bool isip(int a,int b,int c,int d){
    if((a>=0&&b<=255)&&(b>=0&&b<=255)&&(c>=0&&c<=255)&&(d>=0&&d<=255)){
        return true;
    }
    return false;
}