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 <queue>
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main(){

	int w,h;
	int xs,ys;
	int xg,yg;
	int n;
	while(cin>>w>>h&&!(w==0&&h==0)){
		int field[101][101];
		for(int i = 0; i < 101; i++)
			fill(field[i],field[i]+101,0);

		cin>>xs>>ys;
		cin>>xg>>yg;
		xs--;ys--;xg--;yg--;
		cin>>n;
		for(int i = 0; i < n; i++){
			int c,d,x,y;
			cin>>c>>d>>x>>y;
			x--;y--;
			if(d==0){
				for(int j = y; j < 2+y; j++){
					for(int k = x; k < x + 4; k++){
						field[j][k]=c;
					}
				}
			}
			else{
				for(int j = y; j < 4+y; j++){
					for(int k = x; k < x + 2; k++){
						field[j][k]=c;
					}
				}
			}
		}
		// bfs
		int c=field[ys][xs];
		if(c==0){
			cout<<"NG"<<endl;
			continue;
		}
		queue<pair<int,int> > *prv=new queue<pair<int,int> >();
		queue<pair<int,int> > *nxt=new queue<pair<int,int> >();

		const int dy[]={-1,0,0,1};
		const int dx[]={0,-1,1,0};

		bool passed[101][101];
		for(int i = 0; i < 101; i++)
			fill(passed[i],passed[i]+101,false);

		prv->push(make_pair(xs,ys));

		bool fin=false;
		while(prv->size()){
			while(prv->size()){
				pair<int,int> p = prv->front();
				prv->pop();
				if(p.first==yg&&p.second==xg){
					fin=true;
					break;
				}

				if(passed[p.first][p.second])
					continue;
				passed[p.first][p.second]=true;
				for(int i = 0; i < 4; i++){
					int ny=p.first+dy[i];
					int nx=p.second+dx[i];
					if(ny>=0&&nx>=0&&ny<h&&nx<w&&field[ny][nx]==c&&!passed[ny][nx]){
						nxt->push(make_pair(ny,nx));
					}
				}
			}
			if(fin)
				break;
			swap(prv,nxt);
		}
		if(fin){
			cout<<"OK"<<endl;
		}
		else
			cout<<"NG"<<endl;
		delete prv,nxt;
	}

	return 0;
}

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

using namespace std ;

int map[ 100 ][ 100 ] ;
int w ,h ;
int gx ,gy ;
int way ;

struct ST
{
	int x ;
	int y ;
} ;

ST s ,d ;

void ans()
{
	queue< ST > que ;
	int mx[ 4 ] = { 1 ,0 ,0 ,-1 } ;
	int my[ 4 ] = { 0 ,1 ,-1 ,0 } ;
	bool came[ 100 ][ 100 ] = { false } ;
	que.push( s ) ;
	came[ s.y ][ s.x ] = true ;
	while( ! que.empty() )
	{
		s = que.front() ;
		if( s.x == gx && s.y == gy )
		{
			cout << "OK" << endl ;
			return ;
		}
		que.pop() ;
		for( int i = 0 ; i < 4 ; i++ )
		{
			s.x += mx[ i ] ;
			s.y += my[ i ] ;
			if( came[ s.y ][ s.x ] == false && map[ s.y ][ s.x ] == way )
			{
				came[ s.y ][ s.x ] = true ;
				que.push( s ) ;
				s.x -= mx[ i ] ;
				s.y -= my[ i ] ;
			}
		}
	}
	cout << "NG" << endl ;
}


int main()
{
	while( cin >> w >> h ,h )
	{
		int n ;
		int color ,muki ,x ,y ;
		cin >> s.x >> s.y ;
		cin >> gx >> gy ;
		cin >> n ;
		while( n )
		{
			n-- ;
			cin >> color >> muki >> x >> y ;
			x-- ;
			y-- ;
			if( muki )
			{
				for( int i = 0 ; i < 4 ; i++ )
				{
					for( int j = 0 ; j < 2 ; j++ )
					{
						map[ y + i ][ x + j ] = color ;
					}
				}
			}
			else
			{
				for( int i = 0 ; i < 2 ; i++ )
				{
					for( int j = 0 ; j < 4 ; j++ )
					{
						map[ y + i ][ x + j ] = color ;
					}
				}
			}
		}
		gx-- ;
		s.x-- ;
		gy-- ;
		s.y-- ;
		way = map[ s.y ][ s.x ] ;
		ans() ;
	}
	return 0 ;
}