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<iostream>
#include<cstdio>
#include<string>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
using namespace std;
typedef long long ll;
const ll MOD = 1000000007;
const ll INF = (ll)1000000007 * 1000000007;
const double PI = 3.14159265358979;
const double E = 2.718281828459045;
const double root2 = sqrt(2);
typedef pair<int, int> P;
typedef unsigned int ui;
const ll key = 998244353;
struct dat { int tim; int pc; int stu; int log; };
int main() {
	int n, m;
	while (cin >> n >> m,n) {
		int r; cin >> r;
		vector<dat> D; int a, b, c, d;
		for (int i = 0; i < r; i++) {
			cin >> a >> b >> c >> d;
			D.push_back({ a,b,c,d });
		}
		int q; cin >> q; int s, t, u;
		for (int i = 0; i < q; i++) {
			cin >> s >> t >> u;
			int tab[1000] = {}; int cnt = 0;
			for (int j = 0; j < r; j++) {
				if (D[j].stu == u) {
					if (D[j].log == 0) {
						tab[D[j].tim+1-540]--;
					}
					else {
						tab[D[j].tim-540]++;
					}
				}
			}
			for (int j = 1; j < 1000; j++) {
				tab[j] += tab[j - 1];
			}
			for (int j = s-540; j < t-540; j++) {
				if (tab[j] > 0&&tab[j+1]>0)cnt++;
			}
			cout << cnt << endl;
		}
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

int main(){
    int N,M;
    while(1){
        cin >> N >> M;
        if(!N&&!M) return 0;
        int r;cin >> r;
        vector<vector<int>> T(M,vector<int> (1300,0));
        for(int i=0;i<r;i++){
            int t,n,m,s;cin >> t >> n >> m >> s;
            m--;
            if(s==1) T[m][t]++;
            else T[m][t]--;
        }
        for(int i=0;i<M;i++){
            for(int j=0;j<=1260;j++){
                T[i][j+1] += T[i][j];
            }
        }
        int q;cin >> q;
        for(int i=0;i<q;i++){
            int ts,te,m;cin >> ts >> te >> m;
            m--;
            int ans=0;
            for(int j=ts;j<te;j++){
                if(T[m][j]>=1) ans++;
            }
            cout << ans << endl;
        }
    }
}

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++) { // init
      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; エラーデータを弾けないから?
      for(int j=0; j<logg[m].size(); j++) {
	if(logg[m][j].first == logg[m][j].second) {
	  logg[m][j].second = te;
	}
	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;
    }
  }
}

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

struct Record{
  int s;
  int t;
  int n;
  int m;
  Record(int s,int t,int n,int m) : s(s), t(t), n(n), m(m) {;}
};

bool operator<(const Record &l, const Record &r) {
  return (r.t != l.t) ? l.t < r.t : l.m < r.m;
}

int main() {
  int N,M,r,q;
  while(cin>>N>>M, N|M) {
    cin>>r;
    int t,n,m,s,ts,te;
    vector<Record> in;
    for(int i=0; i<r; ++i) {
      cin>>t>>n>>m>>s;
      in.push_back(Record(s,t,n,m));
    }
    cin>>q;
    sort(in.begin(), in.end());

    for(int i=0; i<q; ++i) {
      cin>>ts>>te>>m;
      int use = 0,start = -1,fans = 0;
      vector<pair<int,int> > v;
      for(int j=0; j<in.size(); ++j) {
	if(in[j].m != m) continue;
	if(in[j].s == 1) {
	  if(use == 0 && start == -1)
	    start = in[j].t;
	  use++;
	}
	if(use > 0 && in[j].s == 0) {
	  use--;
	  if(use == 0) {
	    v.push_back(pair<int,int>(start,in[j].t));
	    start = -1;
	  }
	}
      }
      assert(use == 0);
      for(int j=0; j<v.size(); ++j) {
	if(v[j].first >= te || v[j].second <= ts) continue;
	if(v[j].first <= ts && v[j].second >= te) fans += te - ts;
	else if(v[j].first <= ts) fans += v[j].second - ts;
	else if(v[j].second >= te) fans += te - v[j].first;
	else fans += v[j].second - v[j].first;
      }
      cout<<fans<<endl;
    }

  }
}