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++: /*********
深さ優先探索
**********/

#include<iostream>
#include<cstdio>
#include<algorithm>
#define MAX 101

int w,h,n,i,j,ii,count=-1;
int sx,sy,gx,gy;
int c,d,x,y;
int bord[MAX][MAX][MAX]={0};
int num;

//プロトタイプ宣言
int bfs(int x,int y);



int main(){
  
  while(1){

    scanf("%d %d",&w,&h);
    if(w==0 && h==0) break;
    else{
      count++;

    scanf("%d %d",&sx,&sy);
    scanf("%d %d",&gx,&gy);
    scanf("%d",&n);
    
    for(ii=0;ii<n;ii++){
      
      scanf("%d %d %d %d",&c,&d,&x,&y);
      x-=1; y-=1;
      
      if(d==0){
	for(i=0;i<2;i++){
	  for(j=0;j<4;j++){
	    bord[count][y+i][x+j]=c;
	  }
	}
      }
      
      else{
	for(i=0;i<4;i++){
	  for(j=0;j<2;j++){
	    bord[count][y+i][x+j]=c;
	  }
	}
      }
      
    }
    
    //こっからは探索!!
    sx-=1; sy-=1;
    gx-=1; gy-=1;
    num=bord[count][sy][sx];
    
    bfs(sx,sy);
    
    if(bord[count][gy][gx]==-1) printf("OK\n");
    else printf("NG\n");
    }

  }
  return 0;
}



int bfs(int x,int y){
    
  if(x<w && y<h){
    //今いるところを、-1に置き換える
    bord[count][y][x]=-1;
    
    //移動する4方向を調べる
    if(0<=x && x<w && 0<=y-1 && y-1<h && bord[count][y-1][x]==num) bfs(x,y-1);
    if(0<=x-1 && x-1<w && 0<=y && y<h && bord[count][y][x-1]==num) bfs(x-1,y);
    if(0<=x+1 && x+1<w && 0<=y && y<h && bord[count][y][x+1]==num) bfs(x+1,y);
    if(0<=x && x<w && 0<=y+1 && y+1<h && bord[count][y+1][x]==num) bfs(x,y+1);
  }
  
  else return 0;
}

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

#define size_max 100+10

#define Y first
#define X second

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

int map[size_max][size_max];


void paint(int c, int y, int x, int H, int W)
{
	int i, j;
	for (i = y; i < y + H; i++)
	{
		for (j = x; j < x + W; j++)
		{
			map[i][j] = c;
		}
	}
}


void chek(int w, int h)
{
	int i, j;
	for (i = 0; i <= h + 1; i++)
	{
		for (j = 0; j <= w + 1; j++)
		{
			cout << map[i][j];
		}
		cout << endl;
	}
}


typedef pair<int, int> PR;

int main(void)
{
	PR now, tmp;
	queue<PR> QU;

	int w, h;
	int xs, ys, xg, yg, n;
	int c, d, set_x, set_y;

	int i, j;

	while ((cin >> w >> h), w != 0 && h != 0)
	{
		memset(map, 0, sizeof map);

		cin >> xs >> ys >> xg >> yg >> n;

		for (i = 0; i < n; i++)
		{
			cin >> c >> d >> set_x >> set_y;

			if (d == 0)
			{
				paint(c, set_y, set_x, 2, 4);
			}
			else
			{
				paint(c, set_y, set_x, 4, 2);
			}
		}

	//	chek(w, h);

		if (map[ys][xs] == 0)
		{
			cout << "NG\n";
			continue;
		}

		c = map[ys][xs];

		now = make_pair(ys, xs);
		QU.push(now);

		bool goal = false;
		while (!QU.empty())
		{
			now = QU.front();
			QU.pop();

			if (map[now.Y][now.X] == -1)
			{
				map[now.Y][now.X] = -1;

				if (now.Y == yg && now.X == xg)
				{
					goal = true;
					while (!QU.empty())
					{
						QU.pop();
					}
					break;
				}

				for (i = 0; i < 4; i++)
				{
					if (map[now.Y + my[i]][now.X + mx[i]] == c)
					{
						tmp = make_pair(now.Y + my[i], now.X + mx[i]);
						QU.push(tmp);
					}
				}
			}
		}

		if (goal)
		{
			cout << "OK\n";
		}
		else
		{
			cout << "NG\n";
		}

	}

	return 0;
}

C++: #include <bits/stdc++.h>

#define rep(i, j) FOR(i, 0, j)
#define rep2(i, k) for(int i = 1; i <= k; ++i)
#define FOR(i, j, k) for(int i = j; i < k; ++i)
#define INF (1 << 30)

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

int field[105][105], use[105][105];
int h, w, sx, sy, gx, gy, n;
int scol;

void make_map(int x,int y,int chk,int color){
  if(chk == 0){
    for(int i=y;i<y+2;i++){
      for(int j=x;j<x+4;j++) field[i][j] = color;
    }
  }
  else {
    for(int i=y;i<y+4;i++){
      for(int j=x;j<x+2;j++) field[i][j] = color;
    }
  }
}

bool dfs(int x,int y){
  use[y][x] = true;
  if(x == gx && y == gy) return true;
  for(int i=0;i<4;i++){
    int nx = x + dx[i];
    int ny = y + dy[i];
    if(nx >= 0 && nx < w && ny >= 0 && ny < h && field[ny][nx] == field[sy][sx] && !use[ny][nx]) dfs(nx,ny);
  }
  return use[gy][gx];
}

int main() {
	while(cin >> w >> h, w) {
		memset(field, 0, sizeof(field));
		memset(use, false, sizeof(use));
		int scol = 0;
		cin >> sx >> sy >> gx >> gy;
		--sx; --sy; --gx; --gy;
		cin >> n;
		while(n--){
     		int c,d,x,y; cin >> c >> d >> x >> y; --x; --y;
      		make_map(x,y,d,c);
    	}
		rep(i, h + 1){
			rep(j, w + 1) cout << field[i][j] << " ";
			puts("");
  		}
		if(dfs(sx, sy)) cout << "OK" << endl;
		else cout << "NG" << endl; 
	}
	return 0;
}