class Solution {

 public:

     vector<string> restoreIpAddresses(string s) {

         // Start typing your C/C++ solution below

         // DO NOT write int main() function

         int i=,j,k;

         int len = s.size();

         vector<string> result;

         if (len> || len< )

             return result;

         for(i;i<len-;i++){

             for(j=i+;j<len-;j++){

                 for(k=j+;k<len-;k++){

                     string s1 = s.substr(,i+);

                     string s2 = s.substr(i+,j-i);

                     string s3 = s.substr(j+,k-j);

                     string s4 = s.substr(k+);

                     if(isOK(s1) && isOK(s2) && isOK(s3) && isOK(s4)){

                         string s5 = s1 + "." + s2 + "." + s3 + "." + s4;

                         result.push_back(s5);

                     }

                 }

             }

         }

         return result;

     }

     bool isOK(string s){

         int len = s.size();

         if (len> || len <)

             return false;

         else if (==len)

             return true;

         else if (==len){

             return (''!=s.at());

         }else{//3==len

             int a = (s.at()-'')* + (s.at()-'')*+(s.at()-'');

             return (a>= && a<=);

         }

     }

 };