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 <iostream>
using std::cin;
using std::cout;
using std::endl;
#include <algorithm>
using std::pair;
using std::make_pair;
#include <vector>
using std::vector;

typedef vector<int> VI;
typedef pair<int, int> PII;
typedef vector<vector<PII> > VP;

int main(void) {
    while (1) {
        int n; // pc
        int m; // person
        cin >> n >> m;
        if (n == 0 && m == 0) {
            break;
        }

        VI pc(m + 1, 0);
        VI start(m + 1, 0);

        VP time(m + 1);

        int r;
        cin >> r;
        for (int i = 0; i < r; i++) {
            int t;
            int n2; // pc
            int m2; // person
            int s;
            cin >> t >> n2 >> m2 >> s;
            if (s == 1) {
                if (pc[m2] == 0) {
                    start[m2] = t;
                }
                pc[m2]++;
            } else {
                pc[m2]--;
                if (pc[m2] == 0) {
                    int end = t;
                    time[m2].push_back(make_pair(start[m2], end));
                }
            }
        }

        int q;
        cin >> q;
        for (int i = 0; i < q; i++) {
            int s;
            int e;
            int m2;
            cin >> s >> e >> m2;
            int count = 0;

            for (int j = 0; j < (int)(time[m2].size()); j++) {
                int first = time[m2][j].first;
                int second = time[m2][j].second;
                int start;
                int end;
                if (s < first) {
                    start = first;
                } else if (s <= second) {
                    start = s;
                } else {
                    continue;
                }
                if (e < first) {
                    break;
                } else if (e <= second) {
                    end = e;
                } else {
                    end = second;
                }
                count += end - start;
            }
            cout << count << endl;
        }

    }
    return 0;
}

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

#define rep(i,a,b) for(int i=a;i<b;i++)
#define TIME_MAX 1265

typedef vector<int> vi;
typedef vector<vi> vvi;

int main()
{
	while (1)
	{
		int N, M;
		cin >> N >> M;
		if (N == 0) return 0;

		int r; cin >> r;
		vvi count(M + 1, vi(TIME_MAX));
		rep(m, 1, M + 1) rep(t, 0, TIME_MAX) count[m][t] = 0;

		rep(i, 0, r)
		{
			int t, n, m, s;
			cin >> t >> n >> m >> s;
			if (s == 1)
				count[m][t]++;
			else
				count[m][t+1]--;
		}

		rep(m, 1, M + 1) rep(t, 1, TIME_MAX) count[m][t] += count[m][t - 1];
		rep(m, 1, M + 1) rep(t, 0, TIME_MAX) if (count[m][t] > 0) count[m][t] = 1;

		int q; cin >> q;
		rep(i, 0, q)
		{
			int ts, te, m;
			cin >> ts >> te >> m;

			int ans = 0;
			int left = -1;
			rep(t, ts, te + 1)
			{
				if (count[m][t] > 0)
				{
					if (left < 0)
						left = t;
				}
				else
				{
					if (left >= 0)
					{
						ans += t-1 - left;
						left = -1;
					}
				}
			}
			if (left >= 0) ans += te - left;

			cout << ans << endl;
		}
	}
}

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);
        }
    }
}