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<climits>
#include<algorithm>
#include<vector>
#include<map>
#include<queue>
#include<functional>
#include<stack>
#include<list>
#include<string>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) for(int i=0;i<(n);i++)
#define INF INT_MAX/3
#define ALL(a) (a).begin(),(a).end()
#define PII pair<int,int>
#define PCC pair<char,char>
#define PCI pair<char,int>
#define PIC pair<int,char>
#define MP make_pair
#define DEBUG(x) cout<<#x<<": "<<x<<endl

class student
{
public:
	vector<int> IN;
	vector<int> OUT;
	bool T[721];
	bool IsDone = false;
	int check(int S,int E)
	{
		if (!IsDone)
		{
			for (int i = 0; i < IN.size(); i++)
			{
				int start = IN[i];
				int end = OUT[i];
				for (int l = start; l < end; l++)
				{
					T[l] = true;
				}
			}
			IsDone = true;
		}
		int ans = 0;
		for(int i=S;i<E;i++)
		{
			if (T[i] == true)ans++;
		}
		return ans;
	}
	void init()
	{
		IN.clear();
		OUT.clear();
		REP(i, 721)T[i] = false;
		IsDone = false;
	}
};
student S[10001];

int main()
{
	while (1)
	{
		int N, M, r;
		cin >> N >> M >> r;
		if (N == 0)break;
		REP(i, r)
		{
			int t, n, m, b;
			cin >> t >> n >> m >> b;
			t -= 540;
			if (b == 1)S[m].IN.push_back(t);
			else  S[m].OUT.push_back(t);
		}
		int q;
		cin >> q;
		REP(i, q)
		{
			int ans = 0;
			int t1, t2, m;
			cin >> t1 >> t2 >> m;
			t1 -= 540;
			t2 -= 540;
			cout << S[m].check(t1, t2) << endl;
		}
		REP(i, M)
		{
			S[i].init();
		}
	}
	return 0;
}

C++: #include <iostream>
#include <cstring>
using namespace std;

int main() {
	while(1){
		int nn,mm,R,Q;
		int record[721];
		int student[721];
		memset(record,0,sizeof(record));
		memset(student,0,sizeof(student));
		cin >> nn >> mm;
		if(nn==0 && mm==0) break;
		cin >> R;
		for(int i=0;i<R;i++){
			int t,n,m,s;
			cin >> t >> n >> m >> s;
			record[t-540] = s;
			student[t-540] = m;
		}
		cin >> Q;
		for(int i=0;i<Q;i++){
			int s,e,m,count=0,ret=0;
			cin >> s >> e >> m;
			for(int j=0;j<=720;j++){
				if(student[j] == m){
					if(record[j]) count++;
					else count--;
				}
				if(s <= j+540 && j+540 < e){
					if(count) ret++;
				}
			}
			cout << ret << endl;
		}
	}
	return 0;
}

C++: #include<cstdio>
#include<stack>
#include<vector>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
typedef pair<int,int> P;
stack<P> stu[10003];
vector<P> vec[10003];
int N,M,r;
int t[1003],n[1003],m[1003],s[1003];
int q;
int qs[55],qe[55],qm[55];
int main(){
  while(1){
    memset(t,0,sizeof(t));
    memset(n,0,sizeof(n));
    memset(m,0,sizeof(m));
    memset(s,0,sizeof(s));
    memset(qs,0,sizeof(qs));
    memset(qe,0,sizeof(qe));
    memset(qm,0,sizeof(qm));
    for(int i=0;i<10003;i++)vec[i].resize(0);
    for(int i=0;i<10003;i++){
      while(1){
        if(!stu[i].empty()) stu[i].pop();
        else break;
      }}

    scanf("%d%d",&N,&M);
    if(N==0 && M==0) break;
    scanf("%d",&r);
    for(int i=0;i<r;i++){
      scanf("%d%d%d%d",&t[i],&n[i],&m[i],&s[i]);
      if(s[i]==1) stu[m[i]].push(P(t[i],n[i]));
      if(s[i]==0) {
        P p=stu[m[i]].top();
        stu[m[i]].pop();
        if(stu[m[i]].empty()) vec[m[i]].push_back(P(p.first,t[i]));
      }
    }
    scanf("%d",&q);
    int i;
    for(i=0;i<q;i++) {
      scanf("%d%d%d",&qs[i],&qe[i],&qm[i]);

      int res=0;

      int j;
      bool flg1=true;
      for(j=0;j<vec[qm[i]].size();j++){
        if(vec[qm[i]][j].first <=qs[i] && vec[qm[i]][j].second >=qs[i]){
          res+=vec[qm[i]][j].second-qs[i];
          flg1=false;
          break;
        }}
      int l;
      bool flg2=true;
      for(l=0;j<vec[qm[i]].size();l++){
        if(vec[qm[i]][l].first <=qe[i] && vec[qm[i]][l].second >=qe[i]){
          res+=qe[i]-vec[qm[i]][l].first;
          flg2=false;
          break;
        }}

      if(flg1==false && flg2==false){
        for(int ru=j+1;ru<l;ru++) res+=vec[qm[i]][ru].second-vec[qm[i]][ru].first;
      }
      if(flg1==true && flg2==false){
        for(int ru=0;ru<l;ru++)  res+=vec[qm[i]][ru].second-vec[qm[i]][ru].first;
      }
      if(flg1==true && flg2==true){
        for(int ru=0;ru<vec[qm[i]].size();ru++) res+=vec[qm[i]][ru].second-vec[qm[i]][ru].first;
      }
      if(flg1==false && flg2==true){
        for(int ru=j+1;ru<vec[qm[i]].size();ru++)  res+=vec[qm[i]][ru].second-vec[qm[i]][ru].first;
      }



      printf("%d\n",res);

    }

  }
  return 0;
}