Bai2_Rotate_FoldShift

int foldShift(long long key, int addressSize)
{
     string str = to_string(key);
     int size = str.length();
     if (size % addressSize == 0)
     {
         int sum = 0;
         for (int i = 0; i < size ; i = i + addressSize)
         {
             string tmp = str.substr(i,addressSize);
            sum  = sum + stoi(tmp);
         }
         string tong = to_string(sum);
         int t_size = tong.length();
          string res = "";
         if (t_size >= addressSize) res = tong.substr(t_size-addressSize,addressSize);
         else res = tong;
         return stoi(res);
     }
    int sum = 0;
    int temp = 0;
    for (int i = 0; i < size ; i = i + addressSize)
         {
             if (i + addressSize >= size)
             {
                 temp = i;
                 break;
             }
             string tmp = str.substr(i,addressSize);
            sum  = sum + stoi(tmp);
         }
      string tmp = str.substr(temp,size-temp);
      sum = sum + stoi(tmp);
         string tong = to_string(sum);
         int t_size = tong.length();
         string res = "";
           if (t_size >= addressSize) res = tong.substr(t_size-addressSize,addressSize);
         else res = tong;
         return stoi(res);
}
int rotation(long long key, int addressSize)
{

    string str = to_string(key);
    int size = str.length();
    string res = str.substr(0,size-1);
    res = str.substr(size-1,1) + res;
    long long edited = stol(res);
    int result = foldShift(edited,addressSize);
    return result;
}