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<bits/stdc++.h>
using namespace std;
const int INFTY = (1<<21);
int main(){
  int nn,mm,r,q;
  int pc[1001][1441];
  int stu_t[10001][1001];
  int t,n,m,s,ts,te,cnt = 0;
  while(cin >> nn >> mm &&nn&&mm){
    for(int i=0;i<1001;i++){
      for(int j=0;j<1441;j++){
	pc[i][j] = 0;
      }
    }
    cin >> r;
    for(int i=0;i<r;i++){
      cin >> t >> n >> m >> s;
      if(s == 1){
	stu_t[m][n] = t;
      }
      if(s == 0){
	for(int j=stu_t[m][n];j<t;j++){
	  pc[n][j]=m;
	}
      }
    }
    cin >> q;
    for(int i=0;i<q;i++){
      cin >> ts >> te >> m;
      for(int j=ts;j<te;j++){
	for(int k=0;k<=nn;k++){
	  if(pc[k][j] == m){
	    cnt++;
	    break;
	  }
	}
      }
      cout << cnt << endl;
      cnt = 0;
    }
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define MOD 1000000007
#define ADD(X,Y) ((X) = ((X) + (Y)%MOD) % MOD)
typedef long long i64; typedef vector<int> ivec; typedef vector<string> svec; typedef pair<int, int> pi;
int dd[] = { 0, 1, 0, -1, 0 };
#define all(u) begin(u),end(u)
#define mp make_pair
#define pb push_back

int A[10010][1500];
int main()
{
  while(true)
    {
      int N, M;
      scanf("%d%d", &N,&M);
      if(N == 0 && M == 0)break;
      //int A[10010][1500]={0};
      //int A[10010][1500];
      memset(A,0,sizeof(A));
      int r;
      scanf("%d", &r);
      rep(i, r)
	{
	  int t, n, m, s;
	  scanf("%d%d%d%d", &t, &n, &m, &s);
	  if(s == 1)
	    {
	      A[m][t]++;
	    }
	  else
	    {
	      A[m][t+1]--;
	    }
	}
      repi(i, 1, M + 1)
	{
	  rep(t, 1300)
	    {
	      if(t == 0)continue;
	      A[i][t] += A[i][t-1];
	    }
       }

      int q;
      scanf("%d", &q);
      rep(i, q)
	{
	  int ts, te, m;
	  scanf("%d%d%d", &ts,&te,&m);
	  int start = -1;
	  int ans = 0;
	  repi(t, ts, te+1)
	    {
	      if(start == -1)
		{
		  if(A[m][t] > 0)
		    {
		      start = t;
		    }
		}
	      else
		{
		  if(A[m][t] <= 0)
		    {
		      ans += t - start - 1;
		      start = -1;
		    }
		}
	    }
	  if(start != -1)ans += te - start;
	  printf("%d\n", ans);
	}
    }
  return 0;
}

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

using namespace std;

int v[10010][1270];

int main() {
  int N, M, r;
  while (cin >> N >> M, N) {
    for (int i = 0; i <= M; i++) {
      for (int j = 0; j < 1270; j++) {
        v[i][j] = 0;
      }
    }

    cin >> r;
    while (r--) {
      int t, n, m, s;
      cin >> t >> n >> m >> s;
      if (s) {
        v[m][t]++;
      } else {
        v[m][t]--;
      }
    }
    for (int i = 0; i <= M; i++) {
      for (int j = 0; j <= 1260; j++) {
        v[i][j + 1] += v[i][j];
      }
    }

    int q;
    cin >> q;
    while (q--) {
      int s, e, m;
      cin >> s >> e >> m;
      int ans = 0;
      for (int i = s; i < e; i++) {
        ans += (v[m][i] > 0);
      }
      cout << ans << endl;
    }
  }

  return 0;
}

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

#define FOR(i, a, b) for(long long int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(long long int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000 //2000000000
#define LLINF 1000000000000000000 //9000000000000000000
#define PI 3.14159265358979

using namespace std;
typedef long long int ll;
typedef pair< long long int, long long  int> P;


int main(void) {

	while (1) {
		int N, M, r, q;
		int t, n, m, s;
		int ts, te;

		cin >> N >> M;
		vector <vector <int> > dp(M + 1, vector<int>(723, 0));

		cin >> r;
		FOR(i, 1, r) {
			cin >> t >> n >> m >> s;
			if (s == 0) {
				dp[m][t - 538]--;
			}
			else {
				dp[m][t - 539]++;
			}
		}
		FOR(i, 1, M) {
			FOR(j, 1, 722) {
				dp[i][j] += dp[i][j - 1];
			}
		}
		/*cout << endl;
		FOR(i, 1, 722) {
			cout << i+539 << " " << dp[1][i] << endl;
		}*/
		cin >> q;
		FOR(i, 1, q) {
			int total = 0;
			int first = -1, end = -1;
			cin >> ts >> te >> m;
			FOR(j, ts - 539, te - 539) {
				if (first == -1 && dp[m][j] >= 1) {
					first = j;
				}
				if (first != -1 && dp[m][j] <= 0) {

					end = j;
					//cout << "a" << first + 539 << " " << end + 539 << endl;
					total += end - first - 1;
					first = -1;
					end = -1;
				}
				if (j == te - 539 && first != -1) {
					//cout << "b" << first + 539 << " " << j + 539 << endl;
					total += j - first;
				}
			}
			cout << total << endl;
		}
	}

	return 0;
}

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

int main(){
    int N, M;
    while(cin >> N >> M, N != 0){
        vector<vector<int> > student(M+1, vector<int>(1262, 0));
        int r;
        cin >> r;
        for(int i=0;i<r;++i){
            int t, n, m, s;
            cin >> t >> n >> m >> s;
            if(s == 1)student[m][t]++;
            else student[m][t]--;
        }
        for(int i=1;i<=M;++i){
            for(int t=540;t<=1260;++t){
                student[i][t] += student[i][t-1];
            }
        }
        int q;
        cin >> q;
        for(int i=0;i<q;++i){
            int ts, te, m;
            cin >> ts >> te >> m;
            int sum = 0;
            for(int t=ts;t<te;++t){
                if(student[m][t] > 0)sum++;
            }
            cout << sum << endl;
        }
    }


    return 0;
}