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<stack>
#include<cstdio>
using namespace std;

#define X_MAX 100+10
#define Y_MAX 100+10

#define Vertical 1
#define Horizontal 0

int my[4] = { 1,-1,0,0 };
int mx[4] = { 0,0,1,-1 };

struct ST
{
	int came[Y_MAX][X_MAX] = { 0 };
	int now_y;
	int now_x;
};


void paint_V(int*map , int col)
{
	int i;
	for (i = 0; i < 2; i++)
	{
		*(map + i) = col;
	}
}

void paint_H(int*map, int col)
{
	int i;
	for (i = 0; i < 4; i++)
	{
		*(map + i) = col;
	}
}


void chek(int map[Y_MAX][X_MAX],int lx,int ly)
{
	int i, j;
	for (i = 0; i <= ly+1;i++)
	{
		for (j = 0; j <= lx+1; j++)
		{
			cout << map[i][j];
		}
		cout << endl;
	}
}


int main(void)
{
	ST an,tmp;
	stack<ST> ma;

	int lx, ly, n;
	int sx, sy, gx, gy;
	int col, VorH,set_x,set_y;
	int i, j;

	while ((cin >> lx >> ly), lx!=0&&ly!=0)
	{
		int goal = 0;
		int map[Y_MAX][X_MAX] = { 0 };
		cin >> sx >> sy >> gx >> gy >> n;

		for (i = 0; i < n; i++)
		{
			cin >> col >> VorH >> set_x >> set_y;
			if (VorH == Vertical)
			{
				for (j = 0; j < 4; j++)
				{
					paint_V(map[set_y + j] + set_x, col);
				}
			}
			else
			{
				for (j = 0; j < 2; j++)
				{
					paint_H(map[set_y + j] + set_x, col);
				}
			}
		}
		
		int s_col = map[sy][sx];
		if (s_col == 0)
		{
			cout << "NG\n";
			continue;
		}

		an.now_y = sy;
		an.now_x = sx;
		ma.push(an);

		//chek(map, lx, ly);

		while (!ma.empty())
		{
			an = ma.top();
			ma.pop();
			an.came[an.now_y][an.now_x] = 1;

			//printf("y=%d,x=%d\n", an.now_y, an.now_x);
			//chek(an.came, lx, ly);

			if (an.now_y == gy && an.now_x == gx)
			{
				goal = 1;
				break;
			}

			tmp = an;

			for (i = 0; i < 4; i++)
			{
				if (map[an.now_y + my[i]][an.now_x + mx[i]] == s_col && an.came[an.now_y + my[i]][an.now_x + mx[i]] == 0)
				{
					tmp.now_y = an.now_y + my[i];
					tmp.now_x = an.now_x + mx[i];
					ma.push(tmp);
				}
			}

		}
		if (goal == 1)
		{
			while (!ma.empty())
			{
				ma.pop();
			}
			cout << "OK\n";
		}
		else
		{
			cout << "NO\n";
		}


	}
	return 0;
}

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

int  map[100][100];
bool visited[100][100];
int  w,h;
int  xs,ys;
int  xg,yg;
int  n;

int dfs(int x,int y) {
	static int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
	if(x==xg&&y==yg) return 1;
	visited[x][y]=true;
	for(int i=0;i<4;i++) {
		int nx=x+dx[i],ny=y+dy[i];
		if(0<=nx&&nx<w&&0<=ny&&ny<h&&map[x][y]==map[nx][ny]&&!visited[nx][ny]) {
			if(dfs(nx,ny)) return 1;
		}
	}
	return 0;
}

int main() {
	int c,d,x,y;

	while(1) {
		memset(map,0,sizeof(map));
		memset(visited,0,sizeof(visited));
		scanf("%d %d",&w,&h);
		if(w==0&&h==0) break;
		scanf("%d %d",&xs,&ys);xs--;ys--;
		scanf("%d %d",&xg,&yg);xg--;yg--;
		scanf("%d",&n);
		for(int i=0;i<n;i++) {
			scanf("%d %d %d %d",&c,&d,&x,&y);x--;y--;
			int X,Y;
			if(d==1) {
				X=2;Y=4;
			}else {
				X=4;Y=2;
			}
			for(int j=0;j<X;j++) {
				for(int k=0;k<Y;k++) {
					map[x+j][y+k]=c;
				}
			}
		}
		printf("%s\n",dfs(xs,ys)?"YES":"NG");
	}
}

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

int n, w, h, xs, ys, xg, yg, f[105][105] = { 0 }, dx[] = { 0,1,0,-1 }, dy[] = { 1,0,-1,0 }, used[105][105] = { 0 };
bool flag;
void dfs(int y, int x) {
	for (int i = 0; i < 4; i++) {
		int nx = x + dx[i];
		int ny = y + dy[i];
		if (xg == nx&&yg == ny) {
			flag = true;
			return;
		}
		if (used[ny][nx]) continue;
		if (1 <= nx&&nx <= w && 1 <= ny&&ny <= h&&f[ny][nx]>0) {
			used[ny][nx] = 1;
			dfs(ny, nx);
		}
	}
	return;
}

int main() {
	while (1) {
		flag = false;
		cin >> w >> h;
		if (w == 0 && h == 0) return 0;
		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 = 0; j < 2; j++) {
					for (int k = 0; k < 4; k++) {
						f[y + j][x + k] = 1;
					}
				}
			}
			else {
				for (int j = 0; j < 4; j++) {
					for (int k = 0; k < 2; k++) {
						f[y + j][x + k] = 1;
					}
				}
			}
		}
		used[ys][xs] = 1;
		dfs(ys, xs);
		if (flag) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}