Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		M, T, P, R := io.NextInt(), io.NextInt(), io.NextInt(), io.NextInt()
		if M == 0 {
			break
		}
		score := make([]struct{ num, time, index int }, T)
		submit := make([][]int, T)
		for i := 0; i < T; i++ {
			score[i].index = i + 1
			submit[i] = make([]int, P)
		}

		for i := 0; i < R; i++ {
			m, t, p, j := io.NextInt(), io.NextInt()-1, io.NextInt()-1, io.NextInt()
			if j == 0 {
				score[t].num++
				score[t].time += submit[t][p]*20 + m
			} else {
				submit[t][p]++
			}
		}
		sort.SliceStable(score, func(i, j int) bool {
			return score[i].num < score[j].num || score[i].num == score[j].num && score[i].time > score[j].time
		})

		for i := T - 1; i > 0; i-- {
			io.Printf("%d", score[i].index)
			if score[i].num == score[i-1].num && score[i].time == score[i-1].time {
				io.Printf("=")
			} else {
				io.Printf(",")
			}
		}
		io.Println(score[0].index)
	}
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> P;
P info[51][11];
//bool team[51];
vector<P> v;

map<int, P> mp;
//int D[51];
vector<int> order;

//自作の比較関数
bool comp(P lhs, P rhs){
	if(lhs.first != rhs.first){
		return lhs.first < rhs.first;
	}
	if(lhs.second != rhs.second){
		return lhs.second > rhs.second;
	}
}

int main(){
while(1){//start	
	
	
	int M, T, P, R;
	cin >> M >> T >> P >> R;
	if(M == 0 and T == 0 and P == 0 and R == 0) break;
	
	//初期化
	for(int i = 0; i < 51; i++){
		for(int j = 0; j < 11; j++){
			info[i][j].first = 0;
			info[i][j].second = 0;
		}
	}
	bool team[51] = {0};
	int D[51] = {0};
	int OK[51] = {0};
	
	//データを格納
	for(int i = 0; i < R; i++){
		int m, t, p, j;
		cin >> m >> t >> p >> j;
		team[t] = true;
		
		if(j == 0){
			info[t][p].second = m + 20*info[t][p].first;
			OK[t-1] += 1;
		}
		else{
			info[t][p].first += 1;
		}
	}
	
	//vの内部はキーがチーム名(解いた数/合計時間)
	for(int i = 1; i <= T; i++){
			int sum = 0, ok = 0;
			for(int j = 0; j < 11; j++) sum += info[i][j].second;
			//for(int j = 0; j < 11; j++) if(info[i][j].second) ok += 1;
			int tmp = OK[i-1];
			v.push_back(make_pair(tmp, sum));
			mp[i] = make_pair(tmp, sum);
	}
	
	sort(v.begin(), v.end(), comp);
	reverse(v.begin(), v.end());
	//debug
	//for(int i = 0; i < (int)v.size(); i++) cout << v[i].first << " " << v[i].second << endl;
	
	//重複カウンタを作成
	int d = 1;
	D[0] = 1;
	for(int i = 1; i < (int)v.size(); i++){
		if(v[i-1].first == v[i].first and v[i-1].second == v[i].second){
			D[i] = d;
		}
		else{
			d++;
			D[i] = d;
		}
	}
	
	//debug
	//for(int i = 0; i < (int)v.size(); i++) cout << D[i] << endl;
	
	//ソート結果にチーム名を割り当てる
	bool vis[51] = {false};
	for(int i = 0; i < (int)v.size(); i++){
		for(int j = (int)v.size(); 1 <= j; j--){
			if(v[i] == mp[j]){
				if(vis[j] == false){
					order.push_back(j);
					vis[j] = true;
				}
			}
		}
	}
	
	//debug
	//for(int i = 0; i < (int)v.size(); i++) cout << order[i] << endl;
	
	//出力
	//まず重複数を記録する
	int num[51] = {0};
	for(int i = 0; i < 51; i++) num[D[i]] += 1;
	
	string ans = "A";
	int idx = 0;
	for(int i = 1; i <= (int)order.size(); i++){
		if(num[i] == 0) break;
		else if(num[i] == 1){ 
			ans += to_string(order[idx]);
			idx++;
		}
		else{
			for(int j = 0; j < num[i]; j++){
				if(j == num[i]-1) ans += to_string(order[idx]);
				else ans += to_string(order[idx]) + "=";
				idx++;
			}
		}
		ans += ",";
	}
	
	ans.erase(ans.begin() + 0);
	ans.erase(ans.end() - 1);
	cout << ans << endl;
	
	//初期化
	v.clear();
	mp.clear();
	order.clear();
	
	
}//end	
	
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> iP;
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPR(i, n) for (int i = n; i >= 0; i--)
#define FOR(i, m, n) for (int i = m; i < n; i++)

int main() {
    while (1) {
        int M, T, P, R;
        cin >> M >> T >> P >> R;
        if (M == 0) break;
        int mt[60]{}, pt[60]{}, f[60][15]{};
        REP(i, R) {
            int m, t, p, j;
            cin >> m >> t >> p >> j;
            if (j==0) {
                pt[t]++;
                mt[t] += m + f[t][p] * 20;
            } else {
                f[t][p]++;
            }
        }
        vector<pair<iP, int> > ls;
         for (int i = 1; i <= T; i++) {
             ls.push_back({{pt[i],1000000-mt[i]},i});
        }
        sort(ls.rbegin(),ls.rend());
        cout << ls[0].second;
        for(int i=1;i<T;i++){
            if(ls[i-1].first == ls[i].first){
                cout << "=";
            }
            else cout << ",";
            cout << ls[i].second;
        }
        cout << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<vector> 
#include<algorithm>
using namespace std;

class Team{
public:
  int num;
  int solve;
  int time;
  vector<int> plist;
  Team():num(0),solve(0),time(0),plist(vector<int>(11,0)){}
};

bool compare_num(const Team& left, const Team& right){
  return left.num > right.num;
}
bool compare_solve(const Team& left, const Team& right){
  return left.solve > right.solve;
}
bool compare_time(const Team& left, const Team& right){
  return left.time < right.time;
}

int main(){
  int M, T, P, R;
  int m, t, p, j;
  vector<Team> team;
  for(;;){
    scanf("%d %d %d %d", &M, &T, &P, &R);
    if( M == 0 && T == 0 && P == 0 && R == 0)
      return 0;
    for(int i = 0; i < T; i++){  
      Team temp;
      temp.num = i+1;
      team.push_back(temp);
    }
    for(int i = 0; i < R; i++){
      scanf("%d %d %d %d", &m, &t, &p, &j);
      if(j != 0)
	team.at(t-1).plist.at(p) += 1;
      else{
	team.at(t-1).solve += 1; 
	team.at(t-1).time += m;
	team.at(t-1).time += team.at(t-1).plist.at(p) * 20;
      }
    }
    stable_sort(team.begin(),team.end(),compare_num);
    stable_sort(team.begin(),team.end(),compare_time);
    stable_sort(team.begin(),team.end(),compare_solve);
    cout << team.at(0).num;
    for(int i = 1; i < T; i++){
      if(team.at(i-1).solve == team.at(i).solve && team.at(i-1).time == team.at(i).time)
	cout << "=";
      else
	cout << ",";
      cout << team.at(i).num;
    }
    cout << endl;
    team.clear();
  }
}