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 "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int INF = 1e9;
const ll LINF = 1e18;
template<class S,class T> ostream& operator << (ostream& out,const pair<S,T>& o){ out << "(" << o.first << "," << o.second << ")"; return out; }
template<class T> ostream& operator << (ostream& out,const vector<T> V){ for(int i = 0; i < V.size(); i++){ out << V[i]; if(i!=V.size()-1) out << " ";} return out; }
template<class T> ostream& operator << (ostream& out,const vector<vector<T> > Mat){ for(int i = 0; i < Mat.size(); i++) { if(i != 0) out << endl; out << Mat[i];} return out; }
template<class S,class T> ostream& operator << (ostream& out,const map<S,T> mp){ out << "{ "; for(auto it = mp.begin(); it != mp.end(); it++){ out << it->first << ":" << it->second; if(mp.size()-1 != distance(mp.begin(),it)) out << ", "; } out << " }"; return out; }

/*
 <url:http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1148&lang=jp>
 問題文============================================================
 =================================================================
 解説=============================================================
 ================================================================
 */

/*
 1-index
 RangeAdd : [s,t] に xを加算
 RangeSum : [s,t] の総和を出力
 */
struct BIT {
    int N;
    vector<int> bit1;
    vector<int> bit2;
    BIT(int N):N(N) {
        /* BITは[1..N]で扱う */
        bit1.resize(N + 1, 0);
        bit2.resize(N + 1, 0);
    }
    
    void add1(int x, ll val){
        while (x <= N) {
            bit1[x] += val;
            x += x & -x;
        }
    }
    void add2(int x, ll val){
        while (x <= N) {
            bit2[x] += val;
            x += x & -x;
        }
    }
    
    // [l,r]
    void RangeAdd(int l,int r,ll val){
        // Update BIT1
        add1(l,val);
        add1(r+1,-val);
        
        // Update BIT2
        add2(l,val*(l-1));
        add2(r+1,-val*r);
    }
    
    ll sum1(int x){
        ll ret = 0;
        while (x) {
            ret += bit1[x];
            x &= (x - 1);
        }
        return (ret);
    }
    
    ll sum2(int x){
        ll ret = 0;
        while (x) {
            ret += bit2[x];
            x &= (x - 1);
        }
        return (ret);
    }
    
    ll sum(int x){
        return sum1(x)*x - sum2(x);
    }
    // [l,r]
    ll RangeSum(int l,int r){
        return sum(r) - sum(l-1);
    }
};
int N,M;
void solve(){
    int r; cin >> r;
    vector<BIT> BITs(M,BIT(1260));
    vector<int> t(r),n(r),m(r),s(r);
    for(int i = 0; i < r;i++) cin >> t[i] >> n[i] >> m[i] >> s[i];
    for(int i = 0; i < r;i++){
        if(s[i] == 1){
            for(int j = i + 1; j < r;j++){
                if(s[j] == 0 && m[i] == m[j]){
                    BITs[m[i]-1].RangeAdd(t[i],t[j]-1,1);
                    break;
                }
            }
        }
    }
    int q; cin >> q;
    while(q--){
        int ts,te,m; cin >> ts >> te >> m;
        cout << BITs[m-1].RangeSum(ts,te-1) << endl;
    }
}
int main(void) {
    cin.tie(0); ios_base::sync_with_stdio(false);
    while(cin >> N >> M,N){
        solve();
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <cstring>
#include <cstdio>
#define rep(i,a,b) for(int i=(a); i<(b); i++)

using namespace std;
int N , M;

typedef struct data {
  data(int time , int pc) : time(time) , pc(pc){}
  int time , pc;
} data;

int main(){
  while(cin >> N >> M , N + M){
    vector<data> personal_logs[10001];
    int r; cin >> r;
    rep(i, 0, r){
      int time, pc, user, s;
      cin >> time >> pc >> user >> s;
      personal_logs[user].push_back(data(time , pc));
    }
    
    int q; cin >> q;
    rep(i, 0, q){
      int ts, te, user;
      cin >> ts >> te >> user;

      int now_using = 0;
      int last_login[10001];
      memset(last_login , -1 , sizeof(last_login));
      
      int ans = 0;
      int s = 0, e = 0;
      
      rep(j, 0, personal_logs[user].size()){
        int pc = personal_logs[user][j].pc;
        int time = personal_logs[user][j].time;
        if(last_login[pc] == -1){
          last_login[pc] = time;
          if(now_using == 0){
            s = time;
          }
          now_using++;
        } else {
          int login = last_login[pc];
          int logout = time;
          now_using--;
          if(now_using == 0 && !(logout < ts || te < login)){
            e = min(te, logout);
            s = max(ts, s);
            ans += e - s;
          }
          last_login[pc] = -1;
        }
      }
      cout << ans << endl;
    }
  }
  return 0;
}

C++: #include<bits/stdc++.h>
#define rep(i,n) for(int i=0; i<n; i++)
//#define int long long
#define INF 10000000
using namespace std;
int main(){
    int N,M;
    while(1){
        cin >> N >> M;
        int a[1010]={};
        int record[M+10][1300]={};
        if(N == 0 && M== 0) break;
        int r;
        cin >> r;
        rep(i,r){
            int t,n,m,s;
            cin >> t >> n >> m >> s;
            if(a[n] == 0) a[n] = t;
            else {
                for(int j=a[n]; j<t; j++) record[m][j] = 1;
                a[n] = 0;
            }
        }
        int q;
        cin >> q;
        rep(i,q){
            int s,e,me;
            cin >> s >> e >> me;
            int cnt = 0;
            for(int j=s; j<e; j++) cnt += record[me][j];
            cout << cnt << endl;
        }
    }
    return 0;
}