I get The idea of Problem D Today But I was getting WA and I did not know where is the wrong.. After the contest I discovered that my map donot do sorting to vector of string in it ...

why ???

map<char, vector<string>>mp;
for(auto i:mp){
    sort(i.second.begin(), i.second.end());
}

this is the test that my friend give me after contest:

1

1

D

9H 4H