leetcode Bulls and Cows

class Solution { public:     string getHint(string secret, string guess) {     int sum1 = 0;     int sum2 = 0;     string se;     string gu;         for(int i = 0; i < secret.length(); i ++)         { if(secret[i] == guess[i])         sum1 ++;         else         {         se+=secret[i];         gu+=guess[i];         }         }         sort(se.begin(), se.end());         sort(gu.begin(), gu.end());         for(int i = 0, j = 0; i <se.length()&& j < se.length() ; )         {        if(se[i] == gu[j])        {        sum2++;        i++;j++;        }        else if(se[i] < gu[j])        i++;        else        j++;        }         return to_string(sum1) + "A" + to_string(sum2) + "B";     } };