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

using namespace std;

int main()
{
	while(1)
	{
		int m,t,p,r;
		cin >> m >> t >> p >> r;
		if(m==0&&t==0&&p==0&&r==0) break;

		vector < vector<int> > mt(t, vector<int>() );
		vector < vector<int> > pt(t, vector<int>() );
		vector < vector<int> > jt(t, vector<int>() );

		for (int i=0;i<r;i++)
		{
			int M,T,P,J;
			cin >> M >> T >> P >> J;
			mt[T-1].push_back(M);
			pt[T-1].push_back(P);
			jt[T-1].push_back(J);
		}
		
		multimap <int,int> rank;

		for (int i=0;i<t;i++)
		{
			int SC=0,PT=0;
			vector <bool> solved(p);
			for (int j=mt[i].size()-1;j>=0;j--)
			{
				if(!solved[pt[i][j]])
				{
					if(jt[i][j]==0)
					{
						solved[pt[i][j]]=true;
						SC++;
						PT+=mt[i][j];
					}
				}else{
					PT+=20;
				}
			}
			pair <int, int> PAIR;
			PAIR.first = (-(SC*50000)+PT)*5-i;
			PAIR.second = i;
			rank.insert(PAIR);
		}
		
		for (multimap<int, int>::iterator i=rank.begin();i!=(--rank.end());i++)
		{
			cout << i->second + 1 << ((((i->first)+(i->second))==(((++i)->first)+((i)->second)))?"=":",");
			i--;
		}
		cout << (--rank.end())->second + 1 << endl;
	}
	return 0;
}

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

int main(){
    while(true){
        int contestTime, teamCount, probremCount, submitCount;
        cin >> contestTime >> teamCount >> probremCount >> submitCount;
        if(contestTime == 0){
            break;
        }
        int teamPoint[teamCount], teamTime[teamCount], teamPenalty[teamCount][probremCount];
        for(int i = 0; i < teamCount; i++){
            teamPoint[i] = teamTime[i] = 0;
            for(int j = 0; j < probremCount; j++){
                teamPenalty[i][j] = 0;
            }
        }
        for(int i = 0; i < submitCount; i++){
            int m, t, p, j;
            cin >> m >> t >> p >> j;
            t--;
            if(j == 0){
                teamPoint[t]++;
                teamTime[t] += m + teamPenalty[t][p] * 20;
            }else{
                teamPenalty[t][p]++;
            }
        }
        int previousIndex = -1;
        int previousPoint = -1;
        int previousTime = -1;
        for(int i = 0; i < teamCount; i++){
            int maxPoint = 0;
            int topTime = contestTime;
            int topIndex = 0;
            for(int j = 0; j < teamCount; j++){
                if(teamPoint[j] > maxPoint){
                    maxPoint = teamPoint[j];
                    topTime = teamTime[j];
                    topIndex = j;
                }else if(teamPoint[j] == maxPoint){
                    if(topTime >= teamTime[j]){
                        topTime = teamTime[j];
                        topIndex = j;
                    }
                }
            }
            if(i != 0 && maxPoint == previousPoint && topTime == previousTime){
                cout << '=' << topIndex + 1;
            }else if(i != 0){
                cout << ',' << topIndex + 1;
            }else{
                cout << topIndex + 1;
            }
            previousIndex = topIndex;
            previousTime = teamTime[topIndex];
            previousPoint = teamPoint[topIndex];
            teamPoint[topIndex] = -1;
            teamTime[topIndex] = contestTime + 1;
            
        }
            cout << endl;
    }
    return 0;
}