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 <iostream>
#include <queue>
using namespace std;
typedef pair<int,int> P;

int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int map[110][110];
bool maze[110][110];
int xs,ys,xg,yg,w,h;

bool bfs(int col){
	queue<P> que;
	que.push(P(ys,xs));
	maze[ys][xs]=true;

	while(que.size()){
		P p=que.front();que.pop();
		if(p.first==yg && p.second==xg) return true;
		
		for(int i=0;i<4;i++){
			int ny=p.first+dy[i],nx=p.second+dx[i];
			if(ny>0 && ny<=h && nx>0 && nx<=w && !maze[ny][nx] && map[ny][nx]==col){
				maze[ny][nx]=true;
				que.push(P(ny,nx));
			}
		}
	}

	return false;
}

int main(){
	while(cin>>w>>h){
		if(w==0 && h==0) break;
		
		for(int i=0;i<110;i++){
			for(int j=0;j<110;j++){
				map[i][j]=0;
				maze[i][j]=false;
			}
		}

		int n;
		cin>>xs>>ys>>xg>>yg>>n;
		
		for(int i=0;i<n;i++){
			int c,d,x,y;
			cin>>c>>d>>x>>y;
			
			if(d==0){
				for(int j=y;j<y+2;++j){
					for(int k=x;k<x+4;++k){
						map[j][k]=c;
					}
				}
			}else{
				for(int j=y;j<y+4;++j){
					for(int k=x;k<x+2;++k){
						map[j][k]=c;
					}
				}
			}
		}

		if(bfs(map[ys][xs])) cout<<"OK"<<endl;
		else cout<<"NG"<<endl;
	}
	return 0;
}

C++: #include<map>
#include<queue>
#include<cstdio>
#include<cstring>
#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
#define SIZE 102
using namespace std;

typedef pair<int,int> P;

void input_data(void);  //データ入力用関数
void make_mass(void);   //マス作成用関数
void solve(void);       //処理
void clear(void);       //データの初期化

int n;             //ブロックの個数
int w,h;           //ボードの幅、高さ
int goal=0;
int sx,sy,gx,gy;   //スタートの座標、ゴールの座標
int mass[SIZE][SIZE];
int data[SIZE][SIZE];
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int c[SIZE],d[SIZE],x[SIZE],y[SIZE];       //ブロックの色、向き、左上の座標


int main(){

  int i,j;             //カウンタ変数

  while(1){

    /*情報の入力*/
    cin>>w>>h;

    if(w==h && w==0)break; //ループ終了条件

    input_data();

    make_mass();

    solve();

    if(goal==1){
      cout<<"OK"<<endl;
    } else {
      cout<<"NG"<<endl;
      }

  }

  return 0;
}
void input_data(void){

    cin>>sx>>sy;
    cin>>gx>>gy;

    cin>>n;

    for(int i=0;i<n;i++){
      cin>>c[i]>>d[i]>>x[i]>>y[i];

    }

    return;
}
void make_mass(void){

  int i,j;
  int scolor,fcolor;

    /*マスの作成*/
    for(i=0;i<n;i++){
	switch(d[i]){
	case 0:              //横向きなら
	  for(j=0;j<4;j++){
	    mass[y[i]][x[i]+j]=c[i];
	    mass[y[i]+1][x[i]+j]=c[i];
	  }
	  break;
	case 1:              //縦向きなら
	  for(j=0;j<4;j++){
	    mass[y[i]+j][x[i]]=c[i];
	    mass[y[i]+j][x[i]+1]=c[i];
	  }
	  break;
	}
      }

    scolor=mass[sy][sx];
    fcolor=mass[gy][gx];

      for(i=0;i<h;i++){
	for(j=0;j<w;j++){
	  if(scolor!=mass[i][j]){
	    mass[i][j]=0;
	  }
	}
      }

    return;
}
void solve(void){

  int i,j;
  queue<P> que;
  memset(data,-1,sizeof(data));
  que.push(P(sx,sy));     //queにスタート位置の座標を格納
  data[sy][sx]==0;

  while(!que.empty()){    //queが空でない間
    P p=que.front();
    que.pop();

    if(p.first==gx && p.second==gy){
      goal=1;
      /* cout<<" (^q^)くおえうえーーーるえうおおおwwww"<<endl;*/
      break;
    }
    for(i=0;i<4;i++){
      int nx=p.first+dx[i];
      int ny=p.second+dy[i];
      if(nx>=0 && nx<w && ny>=0 && ny<h && mass[ny][nx]!=0 && data[ny][nx]==-1){
	que.push(P(nx,ny));
	data[ny][nx]=data[p.second][p.first]+1;
      }
    }
  }
  return;
}

/*
花火は他人に向けちゃダメだよ。

( ・ω・)o─━・*:・:・(※)`Д´)アヂィ!

*/

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

int board[102][102];
int xg , yg;
int w, h;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
int sc;
bool b;

void dfs(int x , int y){
	if(x==xg&&y==yg) {b=true;return;}
	for(int i=0;i<4;++i){
		int tx=x+dx[i];
		int ty=y+dy[i];
		if(tx<=0||ty<=0||tx>w||ty>h) continue;
		if(board[tx][ty]!=sc || board[tx][ty]==0) continue;
		if(b) continue;
		dfs(tx,ty);
	}
}

int main(){
	while(cin >> w >> h , w||h){
		int xs , ys;
		int n;
		b=false;
		memset(board,0,sizeof(board));
		cin >> xs >> ys >> xg >> yg >> n;
		for(int i=0;i<n;++i){
			int c , d , x , y;
			cin >> c >> d >> x >> y;
			if(d==0){
				for(int k=0;k<2;++k){
					for(int j=0;j<4;++j){
						board[x+j][y+k]=c;
					}
				}
			} else if(d==1){
				for(int k=0;k<4;++k){
					for(int j=0;j<2;++j){
						board[x+j][y+k]=c;
					}
				}
			}
		}
		sc=board[xs][ys];
		int gc=board[xg][yg];
		if(sc!=gc) {}
		else dfs(xs,ys);
		cout << ( b ? "OK" : "NG") << endl;
	}
	return 0;
}

C++: #include <stdio.h>
#include <math.h>
#include <algorithm>
#include <queue>

using namespace std;

int width,height,table[100][100];

bool rangeCheck(int row,int col){
	if(row >= 0 && row <= width-1 && col >= 0 && col <= height-1)return true;
	else{
		return false;
	}
}

void recursive(int row,int col){
	int tmp = table[row][col];
	table[row][col] = 7;

	if(rangeCheck(row-1,col) == true && table[row-1][col] == tmp)recursive(row-1,col);
	if(rangeCheck(row+1,col) == true && table[row+1][col] == tmp)recursive(row+1,col);
	if(rangeCheck(row,col-1) == true && table[row][col-1] == tmp)recursive(row,col-1);
	if(rangeCheck(row,col+1) == true && table[row][col+1] == tmp)recursive(row,col+1);
}

int main(){

	int x_s,y_s,x_g,y_g,n,color,dist,x,y;

	while(true){
		scanf("%d %d",&width,&height);
		if(width == 0 && height == 0)break;

		for(int i = 0; i < height; i++)
		{
			for(int k = 0; k < width; k++)table[i][k] = 0;
		}

		scanf("%d %d",&x_s,&y_s);
		scanf("%d %d",&x_g,&y_g);

		scanf("%d",&n);

		for(int i = 0; i < n; i++){
			scanf("%d %d %d %d",&color,&dist,&x,&y);

			if(dist == 0){
				for(int row = 0; row < 2; row++){
					for(int col = 0; col < 4; col++){
						table[y-1+row][x-1+col] = color;
					}
				}
			}else{
				for(int row = 0; row < 4; row++){
					for(int col = 0; col < 2; col++){
						table[y-1+row][x-1+col] = color;
					}
				}
			}
		}
		recursive(y_s-1,x_s-1);

		if(table[y_g-1][x_g-1] == 7)printf("OK\n");
		else{
			printf("NG\n");
		}
	}
	return 0;
}