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++: //?????????????????????, ?????°???????±\??´?????¨?????????????????\????????\?????????????????´??°??????
//cnt[i] = ??????[i, i + 1)?????????????????°???PC????????£????????????
//cnt[i]???????????????????????£???????????§????????????????????????imos????????¨????????°???????????????
//?????°???????±\??´??????PC??????, ?????°??????0/?????°??¢??????1?????§???????????????????????¨?????????????????????->???????????????????????????

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

void solve() {
	int row_num;
	int t[1000], pc_id[1000], stu_id[1000], is_login[1000];
	int question_num;
	int start, last, stu;
	int i, j;
	
	cin >> row_num;
	for (i = 0; i < row_num; i++) {
		cin >> t[i] >> pc_id[i] >> stu_id[i] >> is_login[i];
	}
	
	cin >> question_num;
	for (i = 0; i < question_num; i++) {
		cin >> start >> last >> stu;
		
		int cnt[1300] = {0};
		for (j = 0; j < row_num; j++) {
			if (stu_id[j] != stu) continue;
			if (is_login[j]) cnt[t[j]]++;
			else cnt[t[j]]--;
		}
		
		for (j = 1; j < 1300; j++) {
			cnt[j] += cnt[j - 1];
		}
		
		int ans = 0;
		for (j = start; j < last; j++) {
			ans += (cnt[j] > 0);
		}
		cout << ans << endl;
	}
}

int main() {
	int pc_num, stu_num;
	while (cin >> pc_num >> stu_num) {
		if (!pc_num) break;
		solve();
	}
	return 0;
}

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

#define MAX_M 10000+1
#define MAX_N 1000

int N, M;
int r, q;

vector< pair<int, int> > ts[MAX_M];
int cnt[MAX_M];
int from[MAX_M];
int main() {
    while (cin >> N >> M) {
        if (N == 0 && M == 0) break;
        for (int i = 0; i < MAX_M; i++) ts[i].clear();
        memset(cnt, 0, sizeof(cnt));
        memset(from, 0, sizeof(from));
        cin >> r;
        for (int i = 0; i < r; i++) {
            int t, n, m, s;
            cin >> t >> n >> m >> s;
            if (s == 1) {
                if (cnt[m] == 0) from[m] = t;
                cnt[m]++;
            } else {
                cnt[m]--;
                if (cnt[m] == 0) 
                    ts[m].push_back(make_pair(from[m], t));
            }
        }
        cin >> q;
        for (int i = 0; i < q; i++) {
            int s, e, m;
            cin >> s >> e >> m;
            int total = 0;
            for (int j = 0; j < ts[m].size(); j++) {
                if (s < ts[m][j].first) {
                    if (e < ts[m][j].second) {
                        total += (e - ts[m][j].first);
                    } else {
                        total += (ts[m][j].second - ts[m][j].first);
                    }
                } else {
                    if (s < ts[m][j].second) {
                        if (e < ts[m][j].second) {
                            total += (e - s);
                        } else {
                            total += (ts[m][j].second - s);
                        }
                    }
                }
                //cout << ts[m][j].first << ' ' << ts[m][j].second << endl;
            }
            cout << total << endl;
        }
    }
    return 0;
}

C++: #include <bits/stdc++.h>

#define FOR(i, a, b) for(long long int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(long long int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000 //2000000000
#define LLINF 1000000000000000000 //9000000000000000000
#define PI 3.14159265358979

using namespace std;
typedef long long int ll;
typedef pair< long long int, long long  int> P;


int main(void) {
	
	while (1) {
		int N, M, r, q;
		int t, n, m, s;
		int ts, te;

		cin >> N >> M;
		vector <vector <int> > dp(M + 1, vector<int>(723, 0));

		cin >> r;
		FOR(i, 1, r) {
			cin >> t >> n >> m >> s;
			if (s == 0) {
				dp[m][t - 538]--;
			}
			else {
				dp[m][t-539]++;
			}
		}
		FOR(i, 1, M) {
			FOR(j, 1, 722) {
				dp[i][j] += dp[i][j - 1];
			}
		}
		/*cout << endl;
		FOR(i, 1, 722) {
			cout << i+539 << " " << dp[1][i] << endl;
		}*/
		cin >> q;
		FOR(i, 1, q) {
			int total = 0;
			int first = -1, end = -1;
			cin >> ts >> te >> m;
			FOR(j, ts-539, te-539) {
				if (first == -1 && dp[m][j] >= 1) {
					first = j;
				}
				if (first != -1 && dp[m][j] <= 0) {
					
					end = j;
					//cout << "a" << first + 539 << " " << end + 539 << endl;
					total += end - first - 1;
					first = -1;
					end = -1;
				}
				if (j == te - 539 && first != -1) {
					//cout << "b" << first + 539 << " " << j + 539 << endl;
					total += j - first;
				}
			}
			cout << total << endl;
		}
	}

	return 0;
}

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

int main()
{
	int N,M,p,t,n,m,s;
	while(cin >> N >> M, N||M)
	{
		vector<short> tim,num,swt;

		cin >> N;
		while(N--)
		{
			cin >> t >> n >> m >> s;
			tim.push_back(t);
			num.push_back(m);
			swt.push_back(s);
		}

		cin >> N;
		while(N--)
		{
			int lg[1024] = {0};

			cin >> t >> s >> m;		
			for(int i=0; i<num.size(); i++)
			{
				if(m==num[i])
				{
					int d = swt[i]*2-1;
					for(int j=tim[i]-540; j<1024; j++)
					{
						lg[j]+=d;
					}
				}
			}


			int a=0;
			for(int i=t-540; i<s-540; i++)
			{
				if(lg[i]>0) a++;
			}
			cout << a << endl;
		}
		
	}
}