class Solution {

 private:

     int strToInt(const string &str)

     {

         int ans = ;

         int len = str.size();

         if(len >  && str[] == '')

         {

             return ;

         }

         for(int i = ; i < len; ++ i)

         {

             ans = (ans *  + str[i] - '');

         }

         return ans;

     }

 public:

     /**

      * @param s the IP string

      * @return All possible valid IP addresses

      */

     vector<string> restoreIpAddresses(string& s) {

         // Write your code here

         int len = s.size();

         vector<string> ans;

         string result;

         string first;

         string second;

         string third;

         string fourth;

         int iFirst,iSecond,iThird,iFourth;

         for(int i = ;i < len - ; ++ i)

         {

             first.push_back(s[i]);

             iFirst = strToInt(first);

             if(iFirst > )

             {

                 break;

             }

             second.clear();

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

             {

                 second.push_back(s[j]);

                 iSecond = strToInt(second);

                 if(iSecond > )

                 {

                     break;

                 }

                 third.clear();

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

                 {

                     third.push_back(s[k]);

                     iThird = strToInt(third);

                     if(iThird > )

                     {

                         break;

                     }

                     fourth.clear();

                     for(int l = k + ;l < len; ++ l)

                     {

                         fourth.push_back(s[l]);

                     }

                     iFourth = strToInt(fourth);

                     if(iFourth <= )

                     {

                         result = first + "." + second + "." + third + "." + fourth;

                         ans.push_back(result);

                     }

                 }

             }

         }

         return ans;

     }

 };