PAT - 1012 The Best Rank 充分利用容器，精准而优雅～

#include < iostream>
#include < map>
#include < vector>
#include < string>



using namespace std;

map<string, map<int, vector<char>>> database;
map<int, vector<string>, greater<int>> math;
map<int, vector<string>, greater<int>> cprogramming;
map<int, vector<string>, greater<int>> english;
map<int, vector<string>, greater<int>> average;
int main(){
    int n;
    int m;
    cin >> n;
    cin >> m;
    string id;
    int mathGrade;
    int cprogrammingGrade;
    int englishGrade;
    for(int i = 0; i < n; i++){
        cin >> id;
        cin >> cprogrammingGrade;
        cin >> mathGrade;
        cin >> englishGrade;
        cprogramming[cprogrammingGrade].push_back(id);
        math[mathGrade].push_back(id);
        english[englishGrade].push_back(id);
        int averageGrade = (mathGrade + cprogrammingGrade + englishGrade) / 3;
        average[averageGrade].push_back(id);
    }
    int count = 1;
    for(map<int, vector<string>>::iterator it = average.begin(); it != average.end(); ++it){
        int tieCount = 0;
        for(vector<string>::iterator itr = it->second.begin(); itr != it->second.end(); ++itr){
            database[*itr][count].push_back('A');
            //cout << "push A=" << it->first << "at" << distance(average.begin(), it) + 1 << endl;
            tieCount++;
        }
        count += tieCount;
    }
    count = 1;
    for(map<int, vector<string>>::iterator it = cprogramming.begin(); it != cprogramming.end(); ++it){
        int tieCount = 0;
        for(vector<string>::iterator itr = it->second.begin(); itr != it->second.end(); ++itr){
            database[*itr][count].push_back('C');
            tieCount++;
        }
        count += tieCount;
    }
    count = 1;
    for(map<int, vector<string>>::iterator it = math.begin(); it != math.end(); ++it){
        int tieCount = 0;
        for(vector<string>::iterator itr = it->second.begin(); itr != it->second.end(); ++itr){
            database[*itr][count].push_back('M');
            tieCount++;
        }
        count += tieCount;
    }
    count = 1;
    for(map<int, vector<string>>::iterator it = english.begin(); it != english.end(); ++it){
        int tieCount = 0;
        for(vector<string>::iterator itr = it->second.begin(); itr != it->second.end(); ++itr){
            database[*itr][count].push_back('E');
            tieCount++;
        }
        count += tieCount;
    }
    for(int i = 0; i < m; i++){
        cin >> id;
        if(database.count(id)){
            cout << database[id].begin()->first << " " << database[id].begin()->second[0] << endl;
        }else{
            cout << "N/A" << endl;
        }
    }
    return 0;
}```