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[101][102];

void DFS(int Y, int X, int c) {
        //cout << Y << " " << X << endl;
        if (F[Y][X] != c || F[Y][X] == 0)
                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 = 0, H = 0;

        while (!(W == H == 0)) {
                cin >> W >> H;
                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>
#include<queue>
#include<vector>
#include<list>

typedef struct block
{
	int x;
	int y;
	int h;
	int w;
	int color;
}block;

block blocks[2000];

std::queue<int> que;
std::list<int> adjacive[2000];

void makelist(int n);
bool BFS(int start,int goal);

int main()
{
	int n,w,h,xs,ys,xg,yg,start,goal;
	while(1)
	{
		while(!que.empty()){que.pop();}
		start=-1;
		goal=-1;
		std::cin>>w>>h;
		if(w==0&&h==0)break;
		std::cin>>xs>>ys>>xg>>yg>>n;
		
		
		for(int i=0;i<n;i++)
		{
			int c,d,x,y;
			std::cin>>c>>d>>x>>y;
			blocks[i].color=c;
			blocks[i].x=x;
			blocks[i].y=y;
			if(d==0)
			{
				blocks[i].h=2;
				blocks[i].w=4;
			}
			else
			{
				blocks[i].h=4;
				blocks[i].w=2;
			}
			if(blocks[i].x<=xs&&blocks[i].x+blocks[i].w-1>=xs&&blocks[i].y<=ys&&blocks[i].y+blocks[i].h-1>=ys)
			{
				start=i;
			}
			else if(blocks[i].x<=xg&&blocks[i].x+blocks[i].w-1>=xg&&blocks[i].y<=yg&&blocks[i].y+blocks[i].h-1>=yg)
			{
				goal=i;
			}
		}

		makelist(n);

		if(BFS(start,goal))
		{
			std::cout<<"OK"<<std::endl;
		}
		else
		{
			std::cout<<"NG"<<std::endl;
		}
	}
	return 0;
}

void makelist(int n)
{
#define x1 blocks[i].x
#define y1 blocks[i].y
#define h1 blocks[i].h
#define w1 blocks[i].w
#define x2 blocks[j].x
#define y2 blocks[j].y
#define h2 blocks[j].h
#define w2 blocks[j].w

	for(int i=0;i<n;i++)
	{
		adjacive[i].clear();
		for(int j=0;j<n;j++)
		{
			if(blocks[i].color==blocks[j].color)
			{
				if((x1==x2+w2&&y1<=y2+h2-1&&y1+h1-1>=y2)||(x2==x1+w1&&y1<=y2+h2-1&&y1+h1-1>=y2)||(y1==y2+h2&&x1<=x2+w2-1&&x1+w1-1>=x2)||(y2==y1+h1&&x1<=x2+w2-1&&x1+w1-1>=x2))
				{
					adjacive[i].push_back(j);
				}
			}
		}
	}
}

bool BFS(int start,int goal)
{
	int survey;

	if(start==-1||goal==-1)return false;

	que.push(start);
	
	while(!que.empty())
	{
		survey=que.front();
		que.pop();
		for(std::list<int>::iterator it=adjacive[survey].begin();it!=adjacive[survey].end();it++)
		{
				que.push(*it);
		}
		adjacive[survey].clear();
		if(survey==goal)
		{
			return true;
		}
	}
	return false;
}

C++: #include<iostream>
#include<algorithm>
#include<string>
using namespace std;
int w,h,xs,ys,xg,yg,n,ban[101][101]={{0},{0}};
const int START=4545191;
const int GOAL=454545;
const int CHECKED=432535;

	bool dfs(int x,int y,int c){
		//cout<<x<<" "<<y<<endl;
		if(ban[x][y+1]==CHECKED&&ban[x+1][y]==CHECKED)return false;
		if(xg==x&&yg==y)return true;
		if(ban[x+1][y]==c){
			ban[x+1][y]=CHECKED;
			if(dfs(x+1,y,c))return true;
		}
		if(ban[x][y+1]==c){
			ban[x][y+1]=CHECKED;
			if(dfs(x,y+1,c))return true;
		}
		return false;
	}


int main(){

	while(cin>>w>>h&&w&&h){
	cin>>xs>>ys>>xg>>yg>>n;
	for(int i=0;i<101;i++)
	for(int j=0;j<101;j++)ban[i][j]=0;
	for(int i=0;i<n;i++){
		int c,d,x,y;
		cin>>c>>d>>x>>y;
		if(!d){
			for(int i=x;i<x+4;i++){
				for(int j=y;j<y+2;j++){
					ban[i][j]=c;
				}
			}
		}
		else{
		for(int i=x;i<x+2;i++){
				for(int j=y;j<y+4;j++){
					ban[i][j]=c;
				}
			}
		}
	}
	if(dfs(xs,ys,ban[xs][ys]))cout<<"OK"<<endl;
	else cout<<"NG"<<endl;
	}
	return 0;
	}