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;

#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define FOR(i, a, b) for(int i=(a);i<(b);i++)
#define REP(i, n) FOR(i, 0, n)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define RREP(i, n) RFOR(i, n, 0)
#define MFOR(i, m) for(auto i=(m).begin();i!=(m).end();i++)
#define ALL(a) (a).begin(), (a).end()
#define SZ(x) ((int)(x).size())

typedef long long int ll;
typedef pair<int, int> P;
typedef pair<ll, ll> Pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vll;
typedef vector<vll> vvll;

const double eps = 1e-10;
const int MOD = 1000000007;
const int INF = 1000000000;
const ll LINF = 1 << 30;

template<typename T>
void printv(vector<T> const& s) {
  REP(i, SZ(s)) {
    cout << s[i] << " ";
  }
  cout << endl;
}

int main () {
  cin.tie(0);
  cout << setprecision(10);

  while(1) {
    int n, m; cin >> n >> m;
    if(n == 0 && m == 0) break;
    vector<vector<vector<P>>> a(m);
    vector<vector<P>> b(m);
    vector<vector<P>> c(m);
    REP(i, m) {
      a[i].resize(n);
    }

    int r; cin >> r;
    REP(i, r) {
      int nowt, nown, nowm, nows; cin >> nowt >> nown >> nowm >> nows;
      nown--; nowm--;
      if(nows == 1) {
        a[nowm][nown].pb(P(nowt, 0));
      } else {
        a[nowm][nown][a[nowm][nown].size()-1].se = nowt;
      }
    }

    REP(i, m) {
      REP(j, n) {
        REP(k, SZ(a[i][j])) {
          b[i].pb(a[i][j][k]);
        }
      }
    }

    if(1) vector<vector<vector<P>>>().swap(a);

    REP(i, m) {
      // cout << "b" << ":" << SZ(b[i]) << endl;
      if(SZ(b[i])) {
        sort(ALL(b[i]));
        c[i].pb(b[i][0]);
      }

      FOR(j, 1, SZ(b[i])) {
        // cout << i << ":" << j << endl;
        if(c[i][SZ(c[i])-1].se <= b[i][j].fi) {
          c[i].pb(b[i][j]);
        } else {
          c[i][SZ(c[i])-1].se = max(c[i][SZ(c[i])-1].se, b[i][j].se);
        }
      }
      // cout << "c:" << SZ(c[i]) << endl;
    }

    if(1) vector<vector<P>>().swap(b);

    // REP(i, m) {
    //   REP(j, SZ(c[i])) {
    //     // cout << i << ":" << j << ":" << c[i][j].fi << ":" << c[i][j].se << endl;
    //   }
    // }

    int q; cin >> q;
    REP(i, q) {
      int ts, te, nowm; cin >> ts >> te >> nowm;
      nowm--;
      int ans = 0;
      REP(j, SZ(c[nowm])) {
        int tmp = min(te, c[nowm][j].se) - max(ts, c[nowm][j].fi);
        if(tmp > 0) ans += tmp;
      }
      cout << ans << endl;
    }
    
  }
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<tuple>

using namespace std;
typedef pair<int, int> pii;

int main(){

    while(1){
        int N, M;
        cin>> N>> M;
        if(!(N||M)) break;
        int r;
        cin>> r;

        int a[M][2000];
        for(int i=0; i<M; i++){
            for(int j=0; j<2000; j++){
                a[i][j]=0;
            }
        }
        for(int i=0; i<r; i++){
            int t, n, m, s;
            cin>> t>> n>> m>> s;
            n--; m--;
            if(s){
                a[m][t]+=1;
            }else{
                a[m][t]-=1;
            }
        }
        for(int i=0; i<M; i++){
            for(int j=1; j<2000; j++){
                a[i][j]+=a[i][j-1];
            }
        }

        int Q;
        cin>> Q;
        for(int i=0; i<Q; i++){
            int s, e, m;
            cin>> s>> e>> m;
            m--;
            int k=0;
            for(int j=s; j<e; j++){
                k+=(a[m][j]>0);
            }
            cout<< k<< endl;
        }
    }

    return 0;
}

C++: // http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1148&lang=jp

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

int main() {
  int N, M;
  while(scanf("%d%d", &N, &M) != EOF && N) {
    vector<int> V[10010]; // 学生mが利用中のコンピュータを管理
    int start[10010]; // 利用開始時刻
    fill(start, start+10010, 0);
    vector<pair<int, int>> T[10010]; // 利用時刻の記録
    int r;
    scanf("%d", &r);
    int t, m, n, s;
    for (int i=0; i<r; i++) {
      scanf("%d%d%d%d", &t, &n, &m, &s);
      if (s) { // ログイン
	V[m].push_back(n);
	if (start[m] == 0) { // 1台もログインしていない場合
	  start[m] = t;
	}
      } else { // ログアウト
	V[m].erase(find(V[m].begin(), V[m].end(), n));
	if (V[m].empty()) { // 1台もログインしていない場合
	  // cerr << "Student " << m << " logs from " << start[m] << " until " << t << endl;
	  T[m].push_back(make_pair(start[m], t));
	  start[m] = 0;
	}
      }
    }
    int q;
    scanf("%d", &q);
    for (int i=0; i<q; i++) {
      int ts, te;
      scanf("%d%d%d", &ts, &te, &m);
      int ans = 0;
      for (unsigned int j=0; j<T[m].size(); j++) {
	int temp = min(te, T[m][j].second) - max(ts, T[m][j].first);
	if (temp > 0) ans+= temp;
      }
      printf("%d\n", ans);
    }
  }
}