Go: package main

import (
	"bufio"
	"os"
	"strings"
	"strconv"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

var (
	dx = []int{0, -1, 0, 1}
	dy = []int{1, 0, -1, 0}
)

func main() {
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		w, _ := strconv.Atoi(buf[0])
		h, _ := strconv.Atoi(buf[1])
		if w == 0 && h == 0 {
			break
		}
		scanner.Scan()
		buf_ := strings.Split(scanner.Text(), " ")
		xs, _ := strconv.Atoi(buf_[0])
		ys, _ := strconv.Atoi(buf_[1])
		scanner.Scan()
		buf__ := strings.Split(scanner.Text(), " ")
		xg, _ := strconv.Atoi(buf__[0])
		yg, _ := strconv.Atoi(buf__[1])
		xs--
		ys--
		xg--
		yg--
		scanner.Scan()
		n, _ := strconv.Atoi(scanner.Text())
		field := make([][]int, 100)
		for i := range  field {
			field[i] = make([]int, 100)
		}
		visited := make([][]bool, 100)
		for i := range visited {
			visited[i] = make([]bool, 100)
		}
		for i := 0; i < n; i++ {
			scanner.Scan()
			buf___ := strings.Split(scanner.Text(), " ")
			c, _ := strconv.Atoi(buf___[0])
			d, _ := strconv.Atoi(buf___[1])
			x, _ := strconv.Atoi(buf___[2])
			y, _ := strconv.Atoi(buf___[3])
			x--
			y--
			switch d {
			case 0:
				for j := 0; j < 4; j++ {
					for k := 0; k < 2; k++ {
						field[x+j][y+k] = c
					}
				}
			case 1:
				for j := 0; j < 2; j++ {
					for k := 0; k < 4; k++ {
						field[x+j][y+k] = c
					}
				}
			}
		}
		if field[xs][ys] != field[xg][yg] || // スタートとゴールの色が等しくないと"NG"
			field[xs][ys] == 0 { // スタートの色が無職
			fmt.Println("NG")
			continue
		}
		Q := make([]Entry, 0)
		visited[xs][ys] = true
		Q = append(Q, Entry{xs, ys})
		for len(Q) > 0 {
			row := Q[0].x
			col := Q[0].y
			Q = Q[1:]
			for i := 0; i < 4; i++ {
				if 0 <= row+dx[i] && row+dx[i] < w &&
					0 <= col+dy[i] && col+dy[i] < h && // 移動可能な範囲内かどうか
					!visited[row + dx[i]][col + dy[i]] && // 訪問済みか
					field[row+dx[i]][col+dy[i]]==field[row][col] { // 色が同じかどうか
						visited[row+dx[i]][col+dy[i]] = true
						Q = append(Q, Entry{row+dx[i],col+dy[i]})
				}
			}
		}
		if visited[xg][yg] {
			fmt.Println("OK")
		} else {
			fmt.Println("NG")
		}
	}
}

type Entry struct {
	x, y int
}

C++: #include<bits/stdc++.h>
using namespace std;
#define ANSWER(x) cout<<x<<endl
#define debug(x) cout<<#x<<": "<<x
const int BA = 1000;
const int INFTY = (1<<21);
int xg,yg,w,h,gc;
int maps[101][101];
int solve(int xs,int ys);
int main(){
  int tate[2] = {2,4};
  int yoko[2] = {4,2};
  int xs,ys,n;
  int c[101],d[101],x[101],y[101];
  while(1){
    fill(maps[0],maps[101],0);
    cin >> w >> h;
    if(w==0 && h==0)break;
    cin >> xs >> ys >> xg >> yg >> n;
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
    }
    for(int i=0;i<n;i++){
      for(int j=y[i];j<y[i]+tate[d[i]];j++){
	for(int k=x[i];k<x[i]+yoko[d[i]];k++){
	  if(j == ys && k == xs)gc = c[i];
	  maps[j-1][k-1] = c[i];
	}
      }
    }
    /* for(int i=0;i<h;i++){
       for(int j=0;j<w;j++){
       cout << maps[i][j];
       }
       cout << endl;
       }*///マップ確認用
    if(solve(ys-1,xs-1))cout << "OK\n";
    else cout << "NG\n";
  }
}
int solve(int ys,int xs){
  if(xs < 0 || ys < 0 || xs > w-1 || ys > h-1 || maps[ys][xs] == 0){
    return 0;
  }
  else if(maps[ys][xs] == maps[yg-1][xg-1]){
    return 1;
  }
  maps[ys][xs] = 0;
  return solve(ys+1,xs) + solve(ys,xs+1)+ solve(ys-1,xs) + solve(ys,xs-1);
}

C++: //
//  main.cpp
//  joi
//
//  Created by 8595198919 on 14/06/09.
//  Copyright (c) 2014年 8595198919. All rights reserved.
//

#include <iostream>
#include <list>
#include <stack>
#include <cstdio>
#define rep(i,n) for(int i = 0;i < n;i++)
#define Rep(i,n) for(int i = 1;i <= n;i++)
#define fs first
#define sc second
#define mp make_pair
using namespace std;

int w,h;
int xs,ys,xg,yg;
int n;
int goal[2];
int dx[4]={1,0,0,-1};
int dy[4]={0,1,-1,0};
int map_[105][105];
bool went[105][105];
int c,d,x,y;

bool search(int x,int y){
    if(map_[x][y]==0)
        return 0;
    if(x==xg&&y==yg)
        return 1;
    rep(i,4){
        int xnext = x +dx[i];
        int ynext = y +dy[i];
        if(went[xnext][ynext])
            continue;
        if(map_[xnext][ynext]==map_[x][y]){
            went[x][y]=true;
            if(search(xnext,ynext))
                return 1;
        }
    }
    return 0;
}


int main(){
    while(scanf("%d %d",&w,&h),(w!=0&&h!=0)){
        rep(i,w+5){
            rep(j,h+5){
                map_[i][j]=0;
                went[i][j]=0;
            }
        }
        scanf("%d %d %d %d %d",&xs,&ys,&xg,&yg,&n);
        xs++,ys++,xg++,yg++;
        rep(i,n){
            scanf("%d %d %d %d",&c,&d,&x,&y);
            x++,y++;
            rep(i,(dx[d]+1)*2){
                rep(j,(dy[d]+1)*2){
                    map_[x+i][y+j] = c;
                }
            }
        }
        if(search(xs,ys))
            cout << "OK" << endl;
        else
            cout <<"NG"<<endl;
    }
}