题解 | #IP地址#

#include <bits/stdc++.h>
using namespace std;
int main() {
    string s;
    while(cin>>s){
        int dotCount = 0;
        for(int i =0;i<s.length();i++)
            if(s[i]=='.')dotCount++;
        if(dotCount!=3)cout<<"No!";
        else{
            vector<int>v;
            while(s.length()!=0){
                if(s.find('.')!=-1)
                    v.push_back(stoi(s.substr(0,s.find('.'))));
                else{
                    v.push_back(stoi(s));
                    break;
                }
                s = s.substr(s.find('.')+1,s.length());
            }
            bool isRight = true;
            for(auto a:v)
                if(a>255 || a<0)isRight=false;
            cout<<(isRight?"Yes!":"No!")<<endl;
        }
    }
}
// 64 位输出请用 printf("%lld")

qd