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 <queue>
#include <algorithm>
using namespace std;

typedef pair<int, int> P;

struct Team {
    int number=0;
    int m = 0, p = 0;
    vector<P> question;
};

bool comp_solved(const Team& e1, const Team& e2){
    return e1.p > e2.p;
}
bool comp_m(const Team& e1, const Team& e2){
    return e1.m < e2.m;
}
bool comp_n(const Team& e1, const Team& e2){
    return e1.number > e2.number;
}

int main(void){
    int M, T, P1, R;
    int m[2001], t[2001], p[2001], j[2001];
    while(cin >> M >> T >> P1 >> R){
    	if(M == 0 && T == 0 && P1 == 0 && R == 0){
    		break;
    	}
    	bool teamJoin[51];
    	for(int i=0;i<T;i++){
    		teamJoin[i] = false;
    	}
        vector<vector<Team> > a;
        vector<vector<Team> > b;
        Team team[51];
        for(int i=0;i<R;i++){
            cin >> m[i] >> t[i] >> p[i] >> j[i];
            team[t[i]-1].number = t[i];
            teamJoin[t[i]-1] = true;
            if(j[i] == 0){
                team[t[i]-1].p++;
                team[t[i]-1].m += m[i];
                if(!team[t[i]-1].question.empty()){
                    int j=0;
                    while(team[t[i]-1].question.begin() + j <= team[t[i]-1].question.end() ) {
                        P ans = team[t[i]-1].question[j];
                        if(ans.first == p[i]){
                            team[t[i]-1].m += ans.second;
                        }
                        j++;
                    }
                }
            }else{
                team[t[i]-1].question.push_back(P(p[i], m[i]));
            }
        }
        sort(team, team+T, comp_solved);
        int cntE=0, cntS=0;
        int minP = team[0].p;
        for(int i=0;i<T;i++){
            if(team[i].p == minP){
                cntE++;
            }else{
                sort(team+cntS,team+cntE,comp_m);
                cntS = cntE + 1;
                cntE = cntS;
                minP = team[i].p;
            }
        }
        int minM = team[0].m;
        cntE=0;
        cntS=0;
        for(int i=0;i<T;i++){
            if(team[i].m == minM){
                cntE++;
            }else{
                sort(team+cntS,team+cntE,comp_n);
                cntS = cntE + 1;
                cntE = cntS;
                minM = team[i].m;
            }
        }
        
        for(int i=0;i<T;i++){
        	if(team[i].number == 0 ){
        		for(int j=T-1;j>=0;j--){
        			if(teamJoin[j] == false){
        				cout << j+1;
        				teamJoin[j] = true;
        				break;
        			}
        		}
        	}else{
        		cout << team[i].number;
        	}
            if(i==T-1){
                break;
            }
            if(team[i].p != team[i+1].p){
                cout << ",";
            }else{
                if(team[i].m != team[i+1].m){
                    cout << ",";
                }else{
                    cout << "=";
                }
            }
        }
        cout << endl;
    }
    return 0;
}

C++: #define _USE_MATH_DEFINES 
#include <iomanip> 
#include <cmath>  
#include<iostream>
#include <fstream>
#include<vector>
#include<algorithm>
#include<bitset>
#include<map>
#include<queue>
#include<stack>
using namespace std;
typedef long long ll;
#define repi(i,a,b) for(ll i = (ll)(a) ; i < (ll)(b) ; i++)
#define repd(i,a,b) for(ll i = (ll)(a) ; i > (ll)(b) ; i--)
#define rd(x) cin >> x
#define wr(x)  cout << x
#define wrln(x) cout << x << endl

int M, T, P, R;

int main() {
	struct team {
		int number, point, time;
		bool operator<(const team& right) const {
			// ポイントは大きい方が↑、同じなら時間小さい方が↑
			return point == right.point ? time > right.time : point < right.point;
		}
	};
	while (1) {
		cin >> M >> T >> P >> R;
		if (M == 0 && T == 0 && P == 0 && R == 0) break;
		vector<team> teams;
		team ttemp;
		repi(i, 0, T) {
			team t;
			t.number = i, t.point = 0, t.time = 0;
			teams.push_back(t);
		}
		int mi, ti, pi, ji;//経過時間、チーム番号、問題番号、ジャッジの種類
		int timetemps[51][11] = {};//[チーム番号][問題番号]
		repi(i, 0, R) {
			cin >> mi >> ti >> pi >> ji;
			if (ji == 0) {
				//正解
				teams[ti - 1].point++;
				teams[ti - 1].time += (timetemps[ti - 1][pi] + mi);
			}
			else {
				//不正解
				timetemps[ti-1][pi] += 20;
			}
		}
		sort(teams.begin(), teams.end());
		reverse(teams.begin(), teams.end());
		repi(i, 0, teams.size()) {
			if (i > 0) {
				if (teams[i].point == teams[i - 1].point && teams[i].time == teams[i - 1].time) {
					wr("=");
				}
				else {
					wr(",");
				}
			}
			wr(teams[i].number + 1);
		}
		cout << endl;
	}
	return 0;
}