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++: //14:17
#include <iostream>
#include <string>
#include <map>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

#define REP(i,k,n) for(int i=k;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)

#define all(v) v.begin(),v.end()
#define INF 1<<30
#define mp make_pair
#define pb push_back

#define fi first
#define se second

#define each(it,c) for(auto it=(c).begin();it!=(c).end();it++)

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
typedef vector<pair<int, int> > vii;

typedef long long ll;
int per[10100][1000];
int ln[10100];//???????????¨????????°?????°
int main(){
	
	//stu[m] [0]?????? t[1]PC n[2]?????°?????? s
	while(1){
		vii stu[10100];
		int n,m;
		int r;
		cin >> n >> m;
		if(n==0&&m==0) break;
		cin >> r;
		rep(i,m){
			ln[i]=0;
			rep(j,1000){
				per[i][j]=0;
			}	
		}
		rep(i,r){
			int t,n,m,s;
			cin >> t >> n >> m >> s;
			m-=1;
			stu[m].pb(make_pair(t,s));
			ln[m]++;
 		}
 		rep(i,m){
 			int ms = 0;
 			int p = 0;
 			rep(j,ln[i]){
 				if(stu[i][j].se==1){

 					if(ms==0){
 						per[i][p++] = stu[i][j].fi;
 					}
 					ms++;
 				}else if(stu[i][j].se==0){
 					if(ms==1){
 						per[i][p++] = stu[i][j].fi;
 					}
 					ms--;
 				}
 			}
 			ln[i]=p;

 		}
 	// 	cout << "debug" << endl;
 	// 	rep(i,m){
		// 	rep(j,ln[i]){
		// 		cout << "j:"<<j<<""<< per[i][j] << " ";
		// 	}
		// 	cout << endl;
		// }
		// cout << endl;


		int q;
		cin >> q;
		rep(i,q){
			int ans =0;
			int ts,te,m;
			cin >> ts >> te >> m;
			m--;
			for(int j=0;j<ln[m]/2;j++){
				ans += max(0,min(te,per[m][j*2+1])-max(ts,per[m][j*2]));
			}
			// cout << "ans" << endl;
			cout << ans << endl;
		}

		

	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
typedef long long i64;

int main(){
    map<pair<int, int>, vector<int> > history;
    map<int, vector<pair<int, int> > > calcedHistory;
    while (true) {
        int N,M;
        cin >> N >> M;
        if(N==0 && M==0) break;
        int r;
        cin >> r;
        rep(i,r){
            int t,n,m,s;
            cin >> t >> n >> m >> s;
            pair<int, int> userandpc = make_pair(m,n);
            if(s==1){
                if(history.find(userandpc)==history.end()){
                    vector<int> vec;
                    vec.push_back(t);
                    history[userandpc]=vec;
                }else{
                    history[userandpc].push_back(t);
                }
                // cout << "student : " << m << " pc : " << n << " set start time at " << t << endl;
            }else{
                // cout << "student : " << m << " pc : " << n << " set end time at " << t << endl;
                int firstTime = history[userandpc].back();
                bool a= true;
                for(int i=0;i<calcedHistory[m].size();i++){
                    pair<int, int> p = calcedHistory[m][i];
                    // cout << "stacked : " << p.first << "~" << p.second << endl;
                    if(p.first<t && p.second>firstTime){
                        calcedHistory[m][i].first=min(p.first,firstTime);
                        calcedHistory[m][i].second=max(p.second,t);
                        a=false;
                        // cout << "changed to " << calcedHistory[m][i].first << "~" << calcedHistory[m][i].second << endl;
                        break;
                    }
                }
                if(a) calcedHistory[m].push_back(make_pair(firstTime,t));
            }
        }
        
        int q;
        cin >> q;
        rep(i,q){
            int ts,te,m;
            cin >> ts >> te >> m;
            int ans=0;
            for(pair<int, int> timepair : calcedHistory[m]){
                if(timepair.second>ts&&te>timepair.first){
                    ans+=min(timepair.second,te)-max(timepair.first,ts);
                }
            }
            cout << ans << endl;
        }
    }
    return 0;
}

C++: #include<iostream>
#include<vector>
using namespace std;
typedef pair<int, int> P;

const int INF = 1000000;

int main() {
  int N, M;
  while (cin >> N >> M and N) {
    int use = 0, r;
    int start, end;
    vector<P> period;
    REP(i, r) {
      int t, n, m, s;
      cin >> t >> n >> m >> s;

      if (use == 0 and s == 1) start = t;
      if (use == 1 and s == 0) {
        end = t;
        period.push_back(P(start, end));
      }

      if (s == 1) use++;
      else use--;
    }
    
    int q;
    REP(i, q) {
      cin >> start >> end;
    }