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 <algorithm>
#include <iostream>
#include <limits.h>
#include <math.h>
#include <set>
#include <stack>
#include <stdlib.h>
#include <string>
#include <vector>

#define el endl
#define fd fixed
#define INF INT_MAX/2-1
#define pb push_back

using namespace std;

class Record
{
public:
  int t;
  int n;
  int m;
  int s;
};

int main() {
  int N, M, r, t, n, m, s, q, st, et, st_tmp;
  while (cin >> N >> M, N | M) {
    cin >> r;
    Record records[r];
    for (int i = 0; i < r; i++) {
      cin >> t >> n >> m >> s;
      records[i].t = t;
      records[i].n = n;
      records[i].m = m;
      records[i].s = s;
    }
    cin >> q;
    while (q--) {
      cin >> st >> et >> m;
      int i = 0, cnt = 0, ut = 0;
      for (int time = 540; time <= 1260; time++) {
        if (records[i].t == time) {
          if (records[i].m == m) {
            if (records[i].s) {
              if (cnt == 0) {
                if (time < st) {
                  st_tmp = st;
                } else {
                  st_tmp = time;
                }
              }
              cnt++;
            } else {
              cnt--;
              if (cnt == 0) {
                if (time > st) {
                  ut += time - st_tmp;
                } else {
                  st_tmp = 0;
                }
              }
            }
          }
          i++;
          time--;
        }
        if (time == et) {
          if (cnt > 0) {
            ut += et-st_tmp;
          }
          break;
        }
      }
      cout << ut << el;
    }
  }
}

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

int main(){
	while(true){
		vector<int> curlog;
		vector< list< pair<int,int> > > log;
		int N,M,r,q;
		cin>>N>>M;
		if(N==0&&M==0)break;
		cin>>r;
		curlog.resize(N);
		log.resize(M);
		for(int i=0;i<r;i++){
			int t,n,m,s;
			cin>>t>>n>>m>>s;
			if(s){
				curlog[n-1]=t;
			}else{
				log[m-1].push_back(pair<int,int>(curlog[n-1],t));
			}
		}
		cin>>q;
		for(int i=0;i<q;i++){
			int s,e,m,a=0;
			list< pair<int,int> > logcop;
			cin>>s>>e>>m;
			logcop=log[m-1];
			logcop.sort();
			for(list< pair<int,int> >::iterator ita=logcop.begin();ita!=logcop.end();++ita){
				if((*ita).second<s||(*ita).first>e)continue;
				int start=(*ita).first,last=(*ita).second;
				list< pair<int,int> >::iterator itb=ita;
				++itb;
				while(itb!=logcop.end()){
					if((*itb).first>start&&(*itb).first<last){
						if((*itb).second>last)last=(*itb).second;
						itb=logcop.erase(itb);
					}else{
						++itb;
					}
				}
				if(start<s)start=s;
				if(last>e)last=e;
				a+=last-start;
			}
			cout<<a<<endl;
		}
	}
	return 0;
}

C++: #include <iostream>
#include <vector>

using namespace std;

const int MaxN = 1001;
const int MaxM = 10001;

int N, M;

int main() {
  int count[MaxM];

  while(cin>>N>>M && !(N==0 && M==0)) {
    vector < vector< pair<int,int> > > logg(MaxM);
    int r;
    cin>>r;
    int t,n,m,s;
    for(int i=0; i<MaxM; i++) { // 初期化
      count[i] = 0;
    }
    for(int i=0; i<r; i++) {
      cin>>t>>n>>m>>s;
      if(s == 1) { // login
	count[m]++;
	if(count[m] == 1) {
	  logg[m].push_back(make_pair(t,t));
	}
      }
      else { // logout
	count[m]--;
	if(count[m] == 0) {
	  logg[m].back().second = t;
	}
      }
    }
    int q;
    cin>>q;
    for(int i=0; i<q; i++) {
      int ts, te, m, ans = 0;
      cin>>ts>>te>>m;
      int ans1, ans2; // 4debug ans1は誤りらしい
      for(int j=0; j<logg[m].size(); j++) {
	if(logg[m][j].first <= te) {
	  ans1 = min(te, logg[m][j].second)-max(ts, logg[m][j].first);
	}
	else {
	  ans1 = 0;
	}
	ans2 = max(0, min(te,logg[m][j].second)-max(ts,logg[m][j].first));
	/*
        if(ans1!=ans2) {
	  cout<<"Q: "<<ts<<" "<<te<<endl;
	  cout<<"why: "<<min(te, logg[m][j].second)-max(ts, logg[m][j].first)<<endl;
	  cout<<"val: "<<logg[m][j].first<<" "<<logg[m][j].second<<endl;
	  cout<<"ans: "<<ans1<<" "<<ans2<<endl;
	}
	*/
        ans += ans1;
      }
      cout<<ans<<endl;
    }
  }
}