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 <algorithm>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;

int w,h,sx,sy,gx,gy,d[100][100],dx[4]={1,0,-1,0},dy[4]={0,1,0,-1},C;
int field[101][101];
const int INF=9999999;
typedef pair<int,int> P;

void bfs(){
	queue<P> que;
	for(int i=0;i<h;i++)for(int j=0;j<w;j++)d[i][j]=INF;
	que.push(P(sy,sx));
	d[sy][sx]=0;
	while(!que.empty()){
		P p=que.front(); que.pop();
		if(p.first==gy&&p.second==gx)break;
		for(int i=0;i<4;i++){
			int ny=p.first+dx[i],nx=p.second+dy[i];
			if(1<=ny&&ny<=h&&1<=nx&&nx<=w&&field[ny][nx]==C&&d[ny][nx]==INF){
			que.push(P(ny,nx));
			d[ny][nx]=d[p.first][p.second]+1;
			}
		}
	}
	if(d[gy][gx]==INF)cout<<"NG"<<endl;
	else cout<<"OK"<<endl;
}

int main() {
	while(cin>>h>>w){
		if(!h)return 0;
		int n,c,di,x,y;
		cin>>sx>>sy>>gx>>gy>>n;
		for(int i=0;i<h;i++)for(int j=0;j<w;j++)field[i][j]=0;
		for(int i=0;i<n;i++){
			cin>>c>>di>>x>>y;
			for(int j=y;j<=y+2+di*2;j++)for(int k=x;k<=x+2+!di*2;k++)field[j][k]=c;
		}
		C=field[1][1];
		bfs();
	}
}

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

int w, h, n;
int sx, sy, gx, gy;
int t[102][102];

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

bool check(int x, int y, int c){
  if(x == gx && y == gy) return true;

  t[y][x] = -1;

  for(int i = 0; i < 4; i++){
    int nx = x + dx[i];
    int ny = y + dy[i];

    if(nx < 0 || w <= nx || ny < 0 || h <= ny || t[ny][nx] != c) continue;
    if(check(nx, ny, c)) return true;
  }

  return false;
}

void putBlock(int c, int d, int x, int y){
  int addX = (d == 0 ? 4 : 2);
  int addY = (d == 0 ? 2 : 4);

  for(int i = y; i < y + addY; i++){
    for(int j = x; j < x + addX; j++){
      t[i][j] = c;
    }
  }
}

int main(){
  while(cin >> w >> h, w || h){
    cin >> sx >> sy; sx--; sy--;
    cin >> gx >> gy; gx--; gy--;
    cin >> n;

    memset(t, -1, sizeof(t));

    for(int i = 0; i < n; i++){
      int c, d, x, y;
      cin >> c >> d >> x >> y;

      x--;
      y--;
      putBlock(c, d, x, y);
    }

    /*
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++){
        printf("%2d", t[i][j]);
      }
      cout<<endl;
    }
    */

    if(t[sy][sx] != -1 && check(sx, sy, t[sy][sx])){
      cout << "OK\n";
    }
    else{
      cout << "NG\n";
    }
  }
}

C++: #include<iostream>
using namespace std;
int w,h,xs,ys,xg,yg,n;
int map[101][101];
string ans;
void fun(int y,int x){
    if(map[y][x]==map[ys][xs]){
        map[y][x]=7;
    }
    else
        return;
    if(x<1||w<x||y<1||h<y)
        return;
    if(map[y+1][x+1]==map[yg][xg]){
        ans="OK";
        return;
    }
    fun(y,x+2);
    fun(y,x-2);
    fun(y+2,x);
    fun(y-2,x);
}
void mc(){
    int c,d,x,y;
    for(int i=0;i<n;i++){
        cin >> c >> d >> x >> y;
        if(d==0){
            for(int j=0;j<2;j++){
                for(int k=0;k<4;k++){
                    map[y+j][x+k]=c;
                }
            }
        }
        else{
            for(int j=0;j<4;j++){
                for(int k=0;k<2;k++){
                    map[y+j][x+k]=c;
                }
            }
        }
    }
}
int main(){
    while(cin >> w >> h,w){
    	ans="NG";
        cin >> xs >> ys >> xg >> yg >> n;
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                map[i][j]=0;
            }
        }
        mc();
        fun(ys,xs);
        cout << ans << endl;
    }
}

C++: #include <iostream>
using namespace std;
int n,w,h;
int M[101][101];
int a,b,c,d;

int walk(int x,int y,int color){
	if(x<1||w<x||y<1||h<y)return 0;
	if(color!=M[x][y])return 0;
	M[x][y]=9;
	walk(x+1,y,color);
	walk(x-1,y,color);
	walk(x,y+1,color);
	walk(x,y-1,color);
	return 0;
}
int main(void){
	while(cin>>w>>h,w||h){
		cin>>a>>b>>c>>d;
		for(int i=1;i<=h;i++){
			for(int j=1;j<=w;j++){
				M[i][j]=0;
			}
		}
		int k;
		cin>>k;
		for(int i=0;i<k;i++){
			int w,x,y,z;
			cin>>w>>x>>y>>z;
			if(x){
				for(int Y=z;Y<z+4;Y++){
					for(int X=y;X<y+2;X++){
						M[Y][X]=w;
					}
				}
			}else{
				for(int Y=z;Y<z+2;Y++){
					for(int X=y;X<y+4;X++){
						M[Y][X]=w;
					}
				}
			}
		}
		walk(a,b,M[a][b]);
		if(M[c][d]==9)cout<<"OK"<<endl;
		else cout<<"NG"<<endl;
	}
	return 0;
}