Go: package main

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

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		_, M := io.NextInt(), io.NextInt()
		if M == 0 {
			break
		}
		r := io.NextInt()
		t, m, s := make([]int, r), make([]int, r), make([]int, r)
		for i := 0; i < r; i++ {
			t[i], _, m[i], s[i] = io.NextInt(), io.NextInt(), io.NextInt()-1, io.NextInt()
		}
		q := io.NextInt()
		for i := 0; i < q; i++ {
			ss, ee, mm := io.NextInt(), io.NextInt(), io.NextInt()-1
			x := make([]int, 1300)
			for j := 0; j < r; j++ {
				if m[j] == mm {
					if s[j] == 1 {
						x[t[j]]++
					} else {
						x[t[j]]--
					}
				}
			}
			for j := 1; j < 1300; j++ {
				x[j] = x[j] + x[j-1]
			}
			ans := 0
			for j := ss; j < ee; j++ {
				if x[j] > 0 {
					ans++
				}
			}
			io.Println(ans)
		}
	}
}

// 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 <stdio.h>

#define M_MAX         10000
#define N_MAX         1000
#define r_MAX         1000
#define q_MAX         50
#define DATASET_MAX   10
#define TS_MIN        540
#define TE_MAX        1260
#define USETIME_MAX   TE_MAX-TS_MIN

struct LogInfo{
    int PCNum;
    int LogInTime;
    int LogOutTime;
};

int LogInCnt[M_MAX];
struct LogInfo LogInfoData[M_MAX][r_MAX];
int UsePCTime[DATASET_MAX];

void VarInit( void ){
    int i;
    int j;
    
    for( i=0; i<M_MAX; i++ ){
        LogInCnt[i] = 0;
        for( j=0; j<r_MAX; j++ ){
            LogInfoData[i][j].PCNum = 0;
            LogInfoData[i][j].LogInTime = 0;
            LogInfoData[i][j].LogOutTime = 0;
        }
    }
}


void RecLogInInfo( int t, int n, int m ){
    LogInfoData[m][LogInCnt[m]].PCNum = n;
    LogInfoData[m][LogInCnt[m]].LogInTime = t;
    LogInCnt[m]++;
}

void RecLogOutInfo( int t, int n, int m ){
    int i;
    
    for( i=0; i<LogInCnt[m]; i++ ){
        if( (LogInfoData[m][i].PCNum == n) && (LogInfoData[m][i].LogOutTime == 0)){
            LogInfoData[m][i].LogOutTime = t;
        }
    }
}

int CalcUsePCTime( int ts, int te, int m ){
    int i,j,t1,t2,Time;
    int Work[USETIME_MAX+1];
    Time = 0;
    
    for( i=0; i<USETIME_MAX+1; i++){
        Work[i] = 0;
    }
    
    for( i=0; i<LogInCnt[m]; i++ ){
        t1 = LogInfoData[m][i].LogInTime-TS_MIN;
        t2 = LogInfoData[m][i].LogOutTime-TS_MIN;
        for( j=t1; j<t2; j++){
            Work[j] = 1;
        }
    }
    
    for( i=ts; i<te; i++){
        if(Work[i-TS_MIN] == 1){
        Time++;
        }
    }
    
    return Time;
}


int main( void ){
    int i,N,M,r,q,t,n,m,s,ts,te;
    int qNum;
    int UseTime;
    
    qNum = 0;
    for( i=0; i<DATASET_MAX; i++ ){
        UsePCTime[i] = 0;
    }
    while( 1 ){
        scanf( " %d %d", &N, &M );
        if( N == 0 ){
            break;
        }
        VarInit();
        scanf( " %d", &r );
        for( i=0; i<r; i++ ){
            scanf( " %d %d %d %d", &t, &n, &m, &s );
            if( s == 1 ){
                RecLogInInfo( t, n, m );
            }else{
                RecLogOutInfo( t, n, m );
            }
        }
        
        scanf( " %d", &q );
        for( i=0; i<q; i++ ){
            scanf( " %d %d %d", &ts, &te, &m );
            UseTime = CalcUsePCTime( ts, te, m );
            printf("%d\n",UseTime);
        }
    }
}

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

vector<pair<int,int>> merge(vector<pair<int,int>> v, pair<int,int> add){
	for(int unsigned i=0;i<v.size();i++){
		if(	(v[i].first <= add.first && add.first <= v[i].second) ||
			(v[i].first <= add.second && add.second <= v[i].second) ||
			(add.first <= v[i].first && v[i].second <= add.second) ){
			v[i] = make_pair(min(v[i].first, add.first), max(v[i].second, add.second));
			return v;
		}
	}
	v.emplace_back(add);
	return v;
}

int main(){
	int N,M;
	while(cin >> N >> M,N!=0&&M!=0){
		int r;
		cin >> r;
		vector<vector<pair<int,int>>> user(M);
		vector<pair<int,int>> user_login(M,make_pair(0,0));
		for(int i=0;i<r;i++){
			int t,n,m,s;
			cin >> t >> n >> m >> s;
			m--;
			if(s && user_login[m].first == 0){
				user_login[m].second = t;
			}
			if(s) user_login[m].first++;
			else user_login[m].first--;
			if(user_login[m].first == 0){
				user[m] = merge(user[m], make_pair(user_login[m].second, t));
			}
		}
		/*for(unsigned int i=0;i<user.size();i++){
			cout << i << ": ";
			for(unsigned int j=0;j<user[i].size();j++){
				cout << "(" << user[i][j].first << ", " << user[i][j].second << ") ";
			}
			cout << endl;
		}*/

		int q;
		cin >> q;
		for(int i=0;i<q;i++){
			int s,e,m;
			cin >> s >> e >> m;
			m--;
			sort(user[m].begin(), user[m].end());
			int ans = 0;
			for(auto x:user[m]){
				if(s <= x.first && x.second <= e){
					//cout << x.second << " " << x.first << endl;
					ans += x.second - x.first;
				} else if(s <= x.first && x.first <= e){
					//cout << e << " " << x.first << endl;
					ans += e - x.first;
				} else if(s <= x.second && x.second <= e){
					//cout << x.second << " " << s << endl;
					ans += x.second - s;
				} else if(x.first <= s && e <= x.second){
					//cout << e << " " << s << endl;
					ans += e - s;
				}
			}
			cout << ans << endl;
		}
	}
	return 0;
}