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>
using namespace std;

int F[102][102] = { 0 };

void DFS(int Y, int X, int c) {
	//cout << Y << " " << X << endl;
	if (F[Y][X] != c)
		return;
	F[Y][X] = 10;
	DFS(Y - 1, X, c);//???
					 //DFS(Y - 1, X+1, A_ito);//??????
	DFS(Y, X + 1, c);//???
					 //DFS(Y + 1, X+1, A_ito);//??????
	DFS(Y + 1, X, c);//???
					 //DFS(Y + 1, X-1, A_ito);//??????
	DFS(Y, X - 1, c);//???
					 //DFS(Y - 1, X-1, A_ito);//??????
}


int main()
{
	int xs, ys, xg, yg, n;
	int c, d, x, y;
	int W = 1, H = 1;

	while ((W != 0) && (H != 0)) {
		cin >> W >> H;
		for (int i = 1;i <= H;i++) {
			for (int j = 1;j <= W;j++) {
				F[i][j] = 6;
			}
		}
		cin >> xs >> ys >> xg >> yg >> n;
		for (int i = 1;i <= n;i++) {
			cin >> c >> d >> x >> y;
			if (d == 0) {
				F[x][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y] = c;
				F[x + 1][y + 1] = c;
				F[x + 2][y] = c;
				F[x + 2][y + 1] = c;
				F[x + 3][y] = c;
				F[x + 3][y + 1] = c;
			}
			if (d == 1) {
				F[x][y] = c;
				F[x + 1][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y + 1] = c;
				F[x][y + 2] = c;
				F[x + 1][y + 2] = c;
				F[x][y + 3] = c;
				F[x + 1][y + 3] = c;
			}
		}
		
			DFS(ys, xs, F[ys][xs]);

		if (F[yg][xg] == 10) {
			cout << "OK" << endl;
		}
		else { cout << "NG" << endl; }
		/*for (int i = 0;i <= H;i++) {
			for (int j = 0;j <= W;j++) {
				F[i][j] = 0;
			}
		}
		*/
	}

	return 0;
}

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

int block[101][101];
int oblock[101][101];
int xg,yg,w,h;

int go (int xs, int ys) {
	//cout << xs << " " << ys << endl;
	oblock[xs][ys] = 1;
	if ( xs > w && ys > h ) {
		return 0;
	}
//	else if ( xs == w && ys == h ) {cout >> "NG" >> endl; return 0;}
	if ( xs > 1 && block[xs-1][ys] == block[xs][ys] && !oblock[xs-1][ys] ){ go( xs-1,ys ); }
	if ( ys > 1 && block[xs][ys-1] == block[xs][ys] && !oblock[xs][ys-1] ){ go( xs,ys-1 ); }
	if ( xs < w && block[xs+1][ys] == block[xs][ys] && !oblock[xs+1][ys] ){ go( xs+1,ys ); }
	if ( ys < h && block[xs][ys+1] == block[xs][ys] && !oblock[xs][ys+1] ){ go( xs,ys+1 ); }
}

int main() {
	while ( cin >> w && cin >> h ) {
		if ( !(w + h) )	break;
		//各ブロックの初期化
		for ( int i = 0; i < w; i++ ) {
			for ( int j = 0; j < h; j++ ) {
				block[i][j] = 0;
				oblock[i][j] = 0;
			}
		}
		int n,xs,ys;
		cin >> xs >> ys;
		cin >> xg >> yg;
		cin >> n;
		//各ブロックの情報の入力
		for ( int i = 0; i < n; i++ ) {
			int c,d,x,y;
			cin >> c >> d >> x >> y;
			int tate,yoko;
			if ( d ) {yoko=2;tate=4;}
			else {yoko=4;tate=2;}
			//カラーの入力
			for ( int j = x; j < x + yoko; j++ ) {
				for ( int k = y; k < y + tate; k++ ) {
					block[j][k] = c;
				}
			}
		}
		/*for ( int i = 0; i < w; i++ ) {
			for ( int j = 0; j < h; j++ ) {
				cout << block[i][j] << " ";
			}
			cout << endl;
		}
		cout << endl;*/
		//経路探索
		if ( block[xs][ys] )	go ( xs, ys );
		if ( oblock[xg][yg] )	cout << "OK" << endl;
		else	cout << "NG" << endl;
		/*for ( int i = 0; i < w; i++ ) {
			for ( int j = 0; j < h; j++ ) {
				cout << oblock[i][j] << " ";
			}
			cout << endl;
		}*/
	}
}

C++: #include<cstdio>
#include<iostream>

using namespace std ;

int mx[] = { 1 ,0 ,0 ,-1 } ;
int my[] = { 0 ,1 ,-1 ,0 } ;

int w ,h ;
int gx ,gy ;

int ok_or_ng( int x ,int y ,bool came[][ 110 ] ,int map[][ 110 ] )
{

	if( x == gx && y == gy )
		return 1 ;
	came[ y ][ x ] = false ;
	map[ y ][ x ] = -1 ;
	for( int i = 0 ; i < 4 ; i++ )
	{
		int xx = x + mx[ i ] ;
		int yy = y + my[ i ] ;
		if( xx > 0 && xx <= w && yy > 0 && yy <= h && came[ yy ][ xx ] != false )
			return ok_or_ng( xx ,yy ,came ,map ) ;
	}
	return 0 ;
}

void wide( int x ,int y ,int c ,int map[][ 110 ] )
{

	for( int i = 0 ; i < 2 ; i++ )
	{
		for( int j = 0 ; j < 4 ; j++ )
			map[ y + i ][ x + j ] = c ;
	}

	return ;
}

void high( int x ,int y ,int c ,int map[][ 110 ] )
{

	for( int i = 0 ; i < 4 ; i++ )
	{
		for( int j = 0 ; j < 2 ; j++ )
			map[ y + i ][ x + j ] = c ;
	}

	return ;
}

int main()
{
	while( cin >> w >> h )
	{
		if( w == h && w == 0 )
		return 0 ;
		bool came[ 110 ][ 110 ] = { false } ;
		int map[ 110 ][ 110 ] = { 0 } ;

		int sx ,sy ;

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

		int n ;
		cin >> n ;					// 0 w	1 h

		int c ,d ,x, y ;
		for( int i = 0 ; i < n ; i++ )
		{
			cin >> c >> d >> x >> y ;
			d ? high( x ,y ,c ,map ) : wide( x ,y ,c ,map ) ;
		}

		c = map[ gy ][ gx ] ;


		for( int i = 1 ; i <= h ; i++ )
		{
			for( int j = 1 ; j <= w ; j++ )
			{
				if( map[ i ][ j ] == c )
					came[ i ][ j ] = true ;
			}
		}

		if( map[ gy ][ gx ] == map[ sy ][ sx ] )
			ok_or_ng( sx ,sy ,came ,map ) ? printf( "OK\n" ) : printf( "NG\n" ) ;
		else
			printf( "NG\n" ) ;
		/*if( came[ gy ][ gx ] ){
		for( int i = 0 ; i <= h + 1 ; i++ )
		{
			for( int j = 0 ; j <= w + 1 ; j++ )
				cout << map[ i ][ j ] ;
			cout << endl ;
		}}*/
	}
}