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>

#define pb push_back
#define mp make_pair
#define MAX 10001

using namespace std;

int main(void)
{
	int n,m;
	int r,q;
	int i1,i2,i3;
	int t,PCn,STm,s;
	int ts,te;
	int time_;
	int c;
	int check;

	while(1){
		cin >> n >> m;
		if(n+m==0) break;

		vector<pair<int,int> > v[MAX];

		cin >> r;
		for(i1=0;i1<r;i1++){
			cin >> t >> PCn >> STm >> s;
			v[STm].pb(mp(t,s));
			/*if(STm==120) {
				cout << t << " " << s << endl;
			}*/
		}

		cin >> q;
		for(i1=0;i1<q;i1++){
			cin >> ts >> te >> STm;
			vector<int> in(1000,0);
			time_=0;
			c=0;
			int count = 0;
			

			for(i2=540;i2<=te;i2++){
				check=0;
				if(c<v[STm].size()){
					if(v[STm][c].first==i2){
						if(v[STm][c].second==1){
							c++;
							count++;
							//cout << count << " " << i2 << endl;
							if(v[STm][c].first==v[STm][c-1].first){
								i2--;
								check=1;
							}
						}
						else {
							c++;
							count--;
							//cout<<count<<" "<<i2<<endl;
							if(v[STm][c].first==v[STm][c-1].first){
								i2--;
								check=1;
							}
						}
					}
				}
				if(count>0 && check==0) in[i2-540]=1;	
			}
			/*for(i2=623-540,i3=1;i2<=673-540;i2++,i3++){
				cout<<in[i2]<<" "<<i3<<endl;
			}*/

			for(i2=ts-540;i2<te-540;i2++){
				if(in[i2]==1) time_++;
			}

			cout << time_ << endl;
		}

	}
	return 0;
}

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

int times[10001][721];

int main() {
    int n, m;
    while( cin >> n >> m, n||m ) {
        memset( times, 0, sizeof(times) );
        int r;
        cin >> r;
        for(int i=0; i<r; i++) {
            int t, n, m, s;
            cin >> t >> n >> m >> s;
            if( s == 1 ) {
                times[m][t-540] += 1;
            } else {
                times[m][t-540] += -1;
            }
        }
        int q;
        cin >> q;
        for(int i=0; i<q; i++) {
            int res = 0;
            int ts, te, m;
            cin >> ts >> te >> m;
            int state = 0;
            for(int i=0; i<te-540; i++) {
                if( times[m][i] != 0 ) {
                    state += times[m][i];
                }
                if( i >= ts-540 && state>0 ) {
                    res++;
                }
            }
            cout << res << endl;
        }
    }
    return 0;
}

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

int main(){
  int N,M;
  while(cin>>N>>M){
    if(N==0)break;
    int r,q;
    int student[M][721];

    for(int i=0;i<M;i++)
      for(int j=0;j<721;j++)
	student[i][j]=0;
  
    cin>>r;
    for(int i=0;i<r;i++){
      int t,n,m,s;
      cin>>t>>n>>m>>s;
      t-=540;m--;
      if(s==1){
	student[m][t]=n;
      }else{
	while(t>0 && student[m][--t]!=n){
	  if(student[m][t]==0) student[m][t]=n;
	}
      }
    }
    cin>>q;
    for(int i=0;i<q;i++){
      int ts,te,m;
      cin>>ts>>te>>m;
      ts-=540;te-=540;m--;
      int ans=0;
      for(int i=ts;i<te;i++){
	if(student[m][i]>0)ans++;
      }
      cout << ans << endl;
    }
  }
  return 0;
}

C++: ///
// File:  1148.cpp
// Author: ymiyamoto
//
// Created on Fri Nov 17 00:20:41 2017
//

#include <cstdint>
#include <iostream>
#include <stack>
#include <vector>

using namespace std;

int32_t main()
{
  while (true) {
    uint32_t N, M;
    cin >> N >> M;
    if (N == 0 && M == 0) break;

    vector<stack<uint32_t>> stacks(M + 1);
    vector<vector<pair<uint32_t, uint32_t>>> used(M + 1);
    uint32_t r;
    cin >> r;
    for (uint32_t _ = 0; _ < r; _++) {
      uint32_t t, n, m, s;
      cin >> t >> n >> m >> s;
      if (s == 0) {
        if (stacks[m].empty()) {
          cerr << t << n << m << s;
          exit(1);
        }
        uint32_t start_time = stacks[m].top();
        stacks[m].pop();
        if (stacks[m].empty()) {
          used[m].push_back({start_time, t});
        }
      } else {
        stacks[m].push(t);
      }
    }

    uint32_t q;
    cin >> q;
    for (uint32_t _ = 0; _ < q; _++) {
      uint32_t s, e, m;
      cin >> s >> e >> m;
      uint32_t count = 0;
      for (auto iter = used[m].begin(); iter < used[m].end(); iter++) {
        uint32_t start = iter->first;
        uint32_t end = iter->second;
        if (start <= s && e <= end) {
          count += e - s;
        } else if (start <= s && end <= e) {
          count += end - s;
        } else if (s <= start && end <= e) {
          count += end - start;
        } else if (s <= start && e <= end) {
          count += e - start;
        }
      }
      cout << count << endl;
    }
  }
  return 0;
}