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 <stdio.h>
#include <queue>
using namespace std;
class node{
public:
	int x,y;
	void set(int xx,int yy){
		x = xx;
		y = yy;
	}
	bool check(int w,int h){
		if(x>=0&&y>=0){
			if(x<=w&&y<=h) return true;
		}
		return false;
	}
	
};

int main(){
	int i,j;
	while(1){
		int w,h;
		int xs,ys,xg,yg,n,c,dir,x,y;
		int color[101][101];
		int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};
		bool visited[101][101];
		queue<node> q;
		node a;
		scanf("%d%d",&w,&h);
		if(w==0&&h==0) break;
		scanf("%d%d",&xs,&ys);
		scanf("%d%d",&xg,&yg);
		scanf("%d",&n);
	
		while(n--){
			scanf("%d%d%d%d",&c,&dir,&x,&y);
			if(dir==0){
				for(i=0;i<2;i++){
					for(j=0;j<4;j++) color[x+j][y+i] = c;
				}
			}
			else{
				for(i=0;i<2;i++){
					for(j=0;j<4;j++) color[x+i][y+j] = c;
				}
			}
		}
		a.set(xs,ys);
		q.push(a);
		visited[a.x][a.y]=true;
		while(!q.empty()){
			a = q.front();
			q.pop();
			for(i=0;i<4;i++){
				a.x += dx[i];
				a.y += dy[i];
				if(!a.check(w,h)&&(color[xs][ys]==color[a.x][a.y])&&!visited[a.x][a.y]){
					q.push(a);
					visited[a.x][a.y] = true;
					if(a.x==xg&&a.y==yg) break;
				}
			}
		}
		if(visited[xg][yg]) printf("OK\n");
		else printf("NG\n");
		for(i=0;i<101;i++){
			for(j=0;j<101;j++) visited[i][j] = false;
		}
	}

	return 0;
}

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

int F[102][102];

bool DFS(int X, int Y, int Xg, int Yg, int c){
	if(F[Y][X] != c){
		return false;
	}else if(F[Y][X] == c && X == Xg && Y == Yg){
		return true;
	}
	F[Y][X] = -1;
	if(DFS(X, Y - 1, Xg, Yg, c)){
		return true;
	}else if(DFS(X + 1, Y, Xg, Yg, c)){
		return true;
	}else if(DFS(X, Y + 1, Xg, Yg, c)){
		return true;
	}else if(DFS(X - 1, Y, Xg, Yg, c)){
		return true;
	}
	
	return false;
}

int main(){
while(true){
	int w, h;
	cin >> w >> h;
	if(w == 0 && h == 0){
		break;
	}
	int xs, ys, xg, yg;
	cin >> xs >> ys >> xg >> yg;
	int n;
	cin >> n;
	for(int y = 0; y < 102; y++){
		for(int x = 0; x < 102; x++){
			F[y][x] = -1;
		}
	}
	for(int i = 0; i < n; i++){
		int c, d, x, y;
		cin >> c >> d >> x >> y;
		if(d == 0){
			for(int X = x; X < x + 4; X++){
				for(int Y = y; Y < y + 2; Y++){
					F[Y][X] = c;
				}
			}
		}else if(d == 1){
			for(int X = x; X < x + 2; X++){
				for(int Y = y; Y < y + 4; Y++){
					F[Y][X] = c;
				}
			}
		}
	}
	if(DFS(xs, ys, xg, yg, F[xg][yg])){
		cout << "OK" << endl;
	}else{
		cout << "NG" << endl;
	}
}
	return 0;
}

C++: #include<iostream>
#include<queue>
#define dr direction
#define cl color
#define fi first
#define se second

using namespace std;
typedef pair<int, int> pii;

class Block{
public:
    int color;// 1~5
    int direction;// 0:-, 1:|
    int x, y;
    void init(int c, int d, int xx, int yy);
};

void Block::init(int c, int d, int xx, int yy){
    color=c;
    direction=d;
    x=xx;
    y=yy;
}

int w, h, xs, ys, xg, yg, n;
int fld[100][100], dis[100][100];
const pii dxdy[]={{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
const int inf=1e8;

string solve(){// bfs
    queue<pii> qu;
    qu.push(make_pair(ys, xs));
    int C=fld[ys][xs];
    fill(dis[0], dis[100], inf);
    dis[ys][xs]=0;

    while(!qu.empty()){
        pii now=qu.front(); qu.pop();
        if(now.fi==yg&&now.se==xg){
            return "OK";
        }

        for(int k=0; k<4; k++){
            pii nx=make_pair(now.fi+dxdy[k].fi, now.se+dxdy[k].se);
            if(!(0<=nx.fi&&nx.fi<h&&0<=nx.se&&nx.se<w)) continue;
            if(fld[nx.fi][nx.se]!=C) continue;
            if(dis[nx.fi][nx.se]!=inf) continue;

            dis[nx.fi][nx.se]=dis[now.fi][now.se]+1;
            qu.push(nx);
        }
    }

    return "NO";
}

int main(){

    while(1){
        cin>> w>> h;
        if(w==0&&h==0) break;
        cin>> xs>> ys>> xg>> yg>> n;
        xs--; ys--; xg--; yg--;
        Block block[n];
        for(int i=0; i<n; i++){
            int c, d, xx, yy;
            cin>> c>> d>> xx>> yy;
            xx--; yy--;
            block[i].init(c, d, xx, yy);
        }

        // make field
        for(int k=0; k<n; k++){
            int X=block[k].x, Y=block[k].y;
            if(block[k].dr==0){
                for(int i=0; i<2; i++){
                    for(int j=0; j<4; j++){
                        fld[Y+i][X+j]=block[k].cl;
                    }
                }
            }else{
                for(int i=0; i<4; i++){
                    for(int j=0; j<2; j++){
                        fld[Y+i][X+j]=block[k].cl;
                    }
                }
            }
        }
/*
        for(int i=0; i<w; i++){
            for(int j=0; j<h; j++){
                cout<< fld[i][j]<<" ";
            }
            cout<< endl;
        }
//*/
        cout<< solve()<< endl;
    }

    return 0;
}