299. Bulls and Cows 自己写已ac

class Solution {
public:
string getHint(string secret, string guess) {
map<char,int> mp;
if(secret.size()==0)return "";
int a=0,b=0;
string ss;
for(int i=0;i<secret.size();i++){
if(secret[i]==guess[i]){
a++;
}
else {
mp[secret[i]]++;
ss+=guess[i];
}
}
for(int i=0;i<ss.size();i++){
if(mp[ss[i]]>0){
b++;
mp[ss[i]]--;
}
}
return to_string(a)+"A"+to_string(b)+"B";
}
};