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;

int main(){

    cin.tie(0);
    ios::sync_with_stdio(false);

    while( true ){

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

        vector<int> correct(t, 0);
        vector<int> time(t, 0);
        vector<vector<int>> incorrect(t, vector<int>(p, 0));

        for(int i = 0; i < r; i++){

            int mi, ti, pi, ji;
            cin >> mi >> ti >> pi >> ji;

            if(ji == 0){
                correct[ti - 1] += 1;
                time[ti - 1] += incorrect[ti - 1][pi - 1] * 20 + mi;
            } else {
                incorrect[ti - 1][pi - 1]++;
            }

        }

        vector<vector<int>> bucket(p + 1, vector<int>(0));

        for(int i = 0; i < t; i++)
            bucket[correct[i]].push_back(i);
/*
        for(auto &x : bucket){
            for(auto &z : x)
                cout << z << ' ';
            cout << endl;
        }
*/
        int count = 0;
        for(int i = bucket.size() - 1; i >= 0; i--) {
            if(bucket[i].size() == 1)
                cout << bucket[i][0] + 1 << ( ++count != t ? "," : "");
            if(bucket[i].size() > 1){
                vector<pair<int, int>> p(bucket[i].size());
                for(int j = 0; j < bucket[i].size(); j++){
                    p[j] = make_pair(time[bucket[i][j]], bucket[i][j]);
                }
                sort(p.begin(), p.end());
                stack<int> st;
                for(int j = 0; j < bucket[i].size(); j++){
                    if(j != bucket[i].size() - 1){
                        if(p[j].first == p[j+1].first) {
                            st.push(p[j].second);
                        } else {
                            if (!st.empty()) {
                                st.push(p[j].second);
                                while(!st.empty()) {
                                    cout << st.top() + 1 << ( ++count != t ? (st.size() != 1 ? "=" : ",") : "");
                                    st.pop();
                                }
                            } else
                                cout << p[j].second + 1 << ( ++count != t ? "," : "");
                        }
                    } else {
                        if (!st.empty()) {
                            st.push(p[j].second);
                            while(!st.empty()) {
                                cout << st.top() + 1 << ( ++count != t ? (st.size() != 1 ? "=" : ",") : "");
                                st.pop();
                            }
                        } else
                            cout << p[j].second + 1 << ( ++count != t ? "," : "");
                    }
                }
            }
        }
        cout << endl;

    }

    return 0;

}

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

int main(){
  while(true){
    int M,T,P,R;
    cin>>M>>T>>P>>R;

    if(M==0&&T==0&&P==0&&R==0)
      break;

    int CP[50],TT[50],PT[50][10];
    for (int i = 0; i < T; i++) {
        CP[i] = TT[i] = 0;
        for (int j = 0; j < P; j++)
            PT[i][j] = 0;
    }

    for (int i = 0; i < R; i++) {
        int m, t, p, j;
        cin >> m >> t >> p >> j;

        if (j == 0) {
            CP[t - 1]++;
            TT[t - 1] += (m + PT[t - 1][p - 1]);
        }
        else {
            PT[t - 1][p - 1] += 20;
        }
    }

    int tnow, tpre = -1;
    bool flg[50];
    for (int i = 0; i < T; i++)
        flg[i] = false;

    for (int i = 0; i < T; i++) {
        tnow = -1;
        for (int j = 0; j < T; j++) {
            if (flg[j])
                continue;

            if (tnow == -1) {
                tnow == j;
            }
            else {
                if (CP[j] > CP[tnow] || (CP[j] == CP[tnow] && TT[j]<=TT[tnow])) {
                    tnow = j;
                }
            }
        }

        if (tpre != -1) {
            if (CP[tnow] == CP[tpre] && TT[tnow] == TT[tpre])
                cout << '=';
            else
                cout << ',';
        }
        cout << tnow + 1;

        flg[tnow] = true;
        tpre = tnow;
    }
    cout << endl;
  }
  return 0;
}