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 <vector>
#include <cstring>
using namespace std;

typedef pair <int, int> PII;
typedef vector<PII> VPII;
typedef vector<VPII> VVPII;
bool U[2000];
int L[1001];

int main( void )
{
    int N, M;
    while ( cin >> N >> M && N && M ) {
        VVPII T( 10001 );
        memset( L, -1, sizeof(L) );
        int r, q;
        int t, n, m, s, ts, te;
        cin >> r;
        for ( int i = 0; i < r; i++ ) {
            cin >> t >> n >> m >> s;
            if ( s ) {
                L[n] = t;
            } else {
                T[m].push_back( PII( L[n], t ) );
                L[n] = -1;
            }
        }
        cin >> q;
        for ( int i = 0; i < q; i++ ) {
            memset( U, false, sizeof(U) );
            int answer = 0;
            cin >> ts >> te >> m;
            for ( VPII ::iterator it = T[m].begin(); it != T[m].end(); it++ ) {
                PII r = *it;
                for ( int j = r.first; j < r.second; j++ ) U[j] = true;
            }
            for ( int j = ts; j < te; j++ ) if ( U[j] ) answer++;
            cout << answer << endl;
        }
    }
    return 0;
}

C++: #include<iostream>

using namespace std;

int main(){
  int n,m;
  while(cin>>n>>m, n+m){
    int (*b)[1300]=new int[10002][1300];
    int r,q;
    for(cin>>r;r>0;r--){
      int t,p,s,l;
      cin >> t >> p >> s >> l;
      while(t<1280) b[s][t++]+=(l!=0?l:-1);
    }
    for(cin>>q;q>0;q--){
      int t1,t2,m,a=0;
      cin >> t1 >> t2 >> m;
      while(t1<t2) a+=(b[m][t1++]>0?1:0);
      cout << a << endl;
    }
    delete [] b;
  }
  return 0;
}

C++: #include<iostream>
#include<cstring>
using namespace std;
struct student{
  int start[1000];
  bool used[721];
};
student S[10000];
int main(){
  int N,M;
  while(cin>>N>>M){
    if(N==0)break;
    int r,q;
    memset(S,0,sizeof(S));  
    cin>>r;
    for(int i=0;i<r;i++){
      int t,n,m,s;
      cin>>t>>n>>m>>s;
      t-=540;m--;n--;
      if(s==1){
	S[m].start[n]=t;
      }else{
	while(t>0 && S[m].start[n]<t)
	  S[m].used[--t]=true;
      }
    }
    cin>>q;
    for(int i=0;i<q;i++){
      int ts,te,m,ans=0;
      cin>>ts>>te>>m;
      ts-=540;te-=540;m--;
      for(int i=ts;i<te;i++){
	if(S[m].used[i]==true)ans++;
      }
      cout << ans << endl;
    }
  }
  return 0;
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<utility>
#include<queue>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<complex>
#define INF 2147483647
#define llINF 9223372036854775807
#define pb push_back
#define mp make_pair 
#define F first
#define S second
#define ll long long

using namespace std;
int main(){
  int n,m;
  while(cin>>n>>m,n+m){
    int r,q;
    cin>>r;
    int stu[m+10][550]={};
    for(int i=0;i<r;i++){
      int a,b,c,d;
      cin>>a>>b>>c>>d;
      if(d){
	stu[c][a-540]++;
      }else{
	stu[c][a-540]--;
      }
    }
    int anss[m+10][550]={};
    for(int i=1;i<=m;i++){
      int po=0;
      for(int j=0;j<=521;j++){
	po+=stu[i][j];
	if(j==0&&po>0)anss[i][j]=1;
	else if(j==0&&po<=0)anss[i][j]=0;
	else if(po>0)anss[i][j]=anss[i][j-1]+1;
	else if(po<=0)anss[i][j]=anss[i][j-1];
	if(i==1)cout<<j<<" "<<anss[1][j]<<endl;
      }
    }
    cin>>q;
    for(int i=0;i<q;i++){
      int fr,to,num;cin>>fr>>to>>num;
      cout<<anss[num][to-540]-anss[num][fr-540]<<endl;
    }
  }
  return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  while(true){
    int n,m;cin >>n>>m;
    if(n==0) break;
    int r,q;
    int time[m+1][721];
    for(int i=0;i<m+1;i++)for(int j=0;j<721;j++)time[i][j]=0;
    cin>>r;
    for(int i=0;i<r;i++){
      int t,pc,stu,s;cin>>t>>pc>>stu>>s;
      t-=540;
      if(s) time[stu][t]++;
      else time[stu][t]--;
    }
    for(int i=1;i<=m;i++)for(int j=1;j<721;j++)time[i][j]+=time[i][j-1];
    cin>>q;
    for(int i=0;i<q;i++){
      int ts,te,stu;cin>>ts>>te>>stu;
      int res=0;
      ts-=540;te-=540;
      for(int j=ts;j<te;j++)if(time[stu][j])res++;
      cout <<res<<endl;
    }
  }
}