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>

#define REP(i, n) for(int i = 0; i < (int) (n); i++)
#define ALL(v) (v).begin(), (v).end()
#define INF 1e9

using namespace std;

struct team{
  int id;
  array<int, 10> penalty;
  int correct;
  int score;
  team(int i) : id(i), penalty({0}), correct(0), score(0) {}
  bool operator<(const team &x)const{
    if(correct < x.correct) return true;
    if(correct > x.correct) return false;
    if(score > x.score) return true;
    if(score < x.score) return false;
    if(id < x.id) return true;
    return false;
  }
  bool operator==(const team &x)const{
    if(correct == x.correct and score == x.score) return true;
    return false;
  }
};

int main(){
  int m, t, r, p;
  while(cin >> m >> t >> p >> r and m + t + p + r){
    vector<team> teams;
    REP(i, t) teams.emplace_back(i+1);
    REP(i, r){
      int mk, tk, pk, jk;
      cin >> mk >> tk >> pk >> jk;
      tk--; pk--;
      if(jk) teams[tk].penalty[pk]++;
      if(!jk) { teams[tk].correct++; teams[tk].score += teams[tk].penalty[pk] * 20 + mk; }
    }
    sort(ALL(teams));
    reverse(ALL(teams));
    REP(i, teams.size()){
      cout << teams[i].id;
      if(i < teams.size()-1) cout << (teams[i] == teams[i+1] ? "=" : ",");
    }
    cout << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <cmath>
#include <cstring>

using namespace std;

int main() {
    int M, T, P, R;
    while (cin >> M >> T >> P >> R){
        int num_solved[T];
        int num_wrong[T][P];
        int total_time[T];

        memset(num_solved, 0, sizeof(num_solved));
        memset(num_wrong, 0, sizeof(num_wrong));
        memset(total_time, 0, sizeof(total_time));

        for (int i = 0; i < R; i++){
            int m, t, p, j;
            cin >> m >> t >> p >> j; t--; p--;
            if (j == 0){
                num_solved[t]++;
                total_time[t] += num_wrong[t][p] * 20 + m;
            } else {
                num_wrong[t][p]++;
            }
        }

        vector<pair<pair<int, int>, int> > vs; 

        for (int i = 0; i < T; i++){
            vs.push_back(make_pair(make_pair(-num_solved[i], total_time[i]), -i)); 
        }
        sort(vs.begin(), vs.end());

        for (int i = 0; i < T; i++){
            if (i > 0){
                if (vs[i].first == vs[i - 1].first){
                    cout << "=";
                } else {
                    cout << ",";
                }
            }
            cout << -vs[i].second + 1 ;
        }
        cout << endl; 
    }
    return 0;
}