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 <set>
using namespace std;

int main(){
    while(true){
        int N, M, r, q, t, n, m, s, ts, te, mm;
        vector<pair<int, pair<int, int> > > lg[10001];
        cin >> N >> M;
        if(!(N||M)) break;
        cin >> r;
        for(int i=0;i<r;++i){
            cin >> t >> n >> mm >> s;
            lg[mm].push_back(make_pair(t, make_pair(n, s)));
        }
        cin >> q;
        for(int i=0;i<q;++i){
            set<int> pc;
            int cnt=0;
            int start=0;
            cin >> ts >> te >> m;
            for(int j=0;j<lg[m].size();++j){
                if(lg[m][j].second.second == 1){
                    pc.insert(lg[m][j].second.first);
                }else{
                    pc.erase(lg[m][j].second.first);
                }
                if(lg[m][j].first < ts){
                    if(!pc.empty()){
                        start = ts;
                    }else{
                        start = 0;
                    }
                }else if(ts <= lg[m][j].first && lg[m][j].first <= te){
                    if(!pc.empty() && start==0){
                        start = lg[m][j].first;
                    }else if(pc.empty() && start!=0){
                        cnt += lg[m][j].first-start;
                        start = 0;
                    }
                }else if(lg[m][j].first > te){
                    if(start!=0) cnt += te-start;
                }
            }
            cout << cnt << endl;
        }
    }
}

C++: #include <stdio.h>

#define M_MAX         10000
#define N_MAX         1000
#define r_MAX         1000
#define q_MAX         50
#define DATASET_MAX   10
#define TS_MIN        540
#define TE_MAX        1260
#define USETIME_MAX   TE_MAX-TS_MIN

struct LogInfo{
  int PCNum;
  int LogInTime;
  int LogOutTime;
};

int LogInCnt[M_MAX];
struct LogInfo LogInfoData[M_MAX][r_MAX];
int UsePCTime[DATASET_MAX];

void VarInit( void ){
  int i;
  int j;
  
  for( i=0; i<M_MAX; i++ ){
    LogInCnt[i] = 0;
    for( j=0; j<r_MAX; j++ ){
      LogInfoData[i][j].PCNum = 0;
      LogInfoData[i][j].LogInTime = 0;
      LogInfoData[i][j].LogOutTime = 0;
    }
  }
}


void RecLogInInfo( int t, int n, int m ){
  LogInfoData[m][LogInCnt[m]].PCNum = n;
  LogInfoData[m][LogInCnt[m]].LogInTime = t;
  LogInCnt[m]++;
}

void RecLogOutInfo( int t, int n, int m ){
  int i;
  
  for( i=0; i<LogInCnt[m]; i++ ){
    if( (LogInfoData[m][i].PCNum == n) && (LogInfoData[m][i].LogOutTime == 0)){
      LogInfoData[m][i].LogOutTime = t;
    }
  }
}

int CalcUsePCTime( int ts, int te, int m ){
  int i,j,t1,t2,Time;
  int Work[USETIME_MAX+1];
  Time = 0;
  
  for( i=0; i<USETIME_MAX+1; i++){
    Work[i] = 0;
  }
  
  for( i=0; i<LogInCnt[m]; i++ ){
    if( LogInfoData[m][i].LogInTime > ts ){
      t1 = LogInfoData[m][i].LogInTime;
    }else if((LogInfoData[m][i].LogInTime <= ts) && (LogInfoData[m][i].LogOutTime >= ts)){
      t1 = ts;
    }else{
      break;
    }
    
    if( LogInfoData[m][i].LogOutTime < te ){
      t2 = LogInfoData[m][i].LogOutTime;
    }else if((LogInfoData[m][i].LogInTime <= te) && (LogInfoData[m][i].LogOutTime >= te)){
      t2 = te;
    }else{
      break;
    }
    
    for( j=t1; j<t2; j++){
      Work[j-TS_MIN] = 1;
    }
  }
  
  for( i=ts; i<=te; i++){
    if(Work[i-TS_MIN] == 1){
      Time++;
    }
  }
  
  return Time;
}


int main( void ){
  int i,N,M,r,q,t,n,m,s,ts,te;
  int qNum;
  int UseTime;
  
  qNum = 0;
  for( i=0; i<DATASET_MAX; i++ ){
    UsePCTime[i] = 0;
  }
  while( 1 ){
    scanf( " %d %d", &N, &M );
    if( N == 0 ){
      break;
    }
    VarInit();
    scanf( " %d", &r );
    for( i=0; i<r; i++ ){
      scanf( " %d %d %d %d", &t, &n, &m, &s );
      if( s == 1 ){
         RecLogInInfo( t, n, m );
      }else{
        RecLogOutInfo( t, n, m );
      }
    }
    
    scanf( " %d", &q );
    for( i=0; i<q; i++ ){
      scanf( " %d %d %d", &ts, &te, &m );
      UseTime = CalcUsePCTime( ts, te, m );
      printf("%d\n",UseTime);
    }
  }
}

C++: #include <iostream>
#include <vector>
#include <stack>
using namespace std;
int main(){
	int N,M;
	while(cin>>N>>M){
		if(N==0 && M==0) break;
		int r,q;
		vector<int> pc(N+1,0);
		vector<vector<int> >time(M+1,vector<int>(1261,0));
		cin>>r;
		for(int i=0;i<r;i++){
			int t,n,m,s;
			cin>>t>>n>>m>>s;
			if(s==1){
				time[m][t]=1;
				pc[n]=t;
			}else if(s==0){
				for(int j=pc[n];j<t;j++){
					time[m][j]=1;
				}
				pc[n]=0;
			}
		}
		cin>>q;
		for(int i=0;i<q;i++){
			int ts,te,mn,count=0;
			cin>>ts>>te>>mn;
			for(int j=ts;j<te;j++){
				if(time[mn][j]==1) count++;
			}
			cout<<count<<endl;
		}
	}
	return 0;
}