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<map>
#include<queue>
#include<cstdio>
#include<cstring>
#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
#define SIZE 110
using namespace std;

typedef pair<int,int> P;

void make_mass(void);   //マス作成用関数
void solve(void);       //処理

int n;             //ブロックの個数
int w,h;           //ボードの幅、高さ
int goal=0;        //迷路になっているか
int scolor;        //スタート位置の色
int sx,sy,gx,gy;   //スタートの座標、ゴールの座標
int mass[SIZE][SIZE];
int data[SIZE][SIZE];
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int c[SIZE],d[SIZE],x[SIZE],y[SIZE];       //ブロックの色、向き、左上の座標


int main(){

  int i,j;             //カウンタ変数

  while(1){

    /*情報の入力*/
    cin>>w>>h;

    if(w==h && w==0){break;}
    
    cin>>sx>>sy;
    cin>>gx>>gy;  
    cin>>n;
    
    for(i=0;i<n;i++){
      cin>>c[i]>>d[i]>>x[i]>>y[i];
      
    }
    
    make_mass();

    solve();
     
    if(goal==1){
      cout<<"OK"<<endl;
      goal=0;
    } else if(goal==0){
      cout<<"NG"<<endl;
      }
  }
  
  return 0;
}
void make_mass(void){
  
  int i,j;

  memset(mass,0,sizeof(mass));

  /*マスの作成*/
  for(i=0;i<n;i++){
    if(d[i]==0){       //横向きなら
      for(j=0;j<4;j++){
	mass[y[i]][x[i]+j]=c[i];
	mass[y[i]+1][x[i]+j]=c[i];
      }
    }
    if(d[i]==1){              //縦向きなら
      for(j=0;j<4;j++){
	mass[y[i]+j][x[i]]=c[i];
	mass[y[i]+j][x[i]+1]=c[i];
      }
    }
  }
  
  scolor=mass[sy][sx];

  
  return;
}
void solve(void){
  
  int i,j;
  queue<P> que;
  memset(data,-1,sizeof(data));
  que.push(P(sx,sy));     //queにスタート位置の座標を格納
  data[sy][sx]=0;
  
  while(!que.empty()){    //queが空でない間
    P p=que.front();
    que.pop();
    
    if(p.first==gy && p.second==gx){
      goal=1;
      /* cout<<" (^q^)くおえうえーーーるえうおおおwwww"<<endl;*/
      break;
    }
    for(i=0;i<4;i++){
      int nx=p.first+dx[i];
      int ny=p.second+dy[i];
      if(nx>=0 && nx<w && ny>=0 && ny<h && mass[ny][nx]==scolor && data[ny][nx]==-1){
	que.push(P(nx,ny));
	data[ny][nx]=1;
      }
    }
  }
  return;
}
/*
花火は他人に向けちゃダメだよ。

( ・ω・)o─━・*:・:・(※)`Д´)アヂィ!

*/

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

int map[101][101];
int w,h; 
int color;
int xg,yg;

bool dfs(int y,int x) {
  if ( map[y][x] != color ) return 0;
  map[y][x] = 10;
  if ( y-1 >= 1 ) dfs( y-1 , x );
  if ( y+1 <= h ) dfs( y+1 , x );
  if ( x-1 >= 1 ) dfs( y , x-1 );
  if ( x+1 <= w ) dfs( y , x+1 );
  
  if ( map[yg][xg]==10 ) return 1; 
  return 0;

}

int main() {
  while ( cin >> w >> h ,w+h ) {
    for(int i=1; i<=h; i++) {
      for(int j=1; j<=w; j++) map[i][j]=0;
    }
    int xs,ys; cin >> xs >> ys;
    cin >> xg >> yg;
    int n; cin >> n;
    while ( n > 0 ) {
      n--;
      int c,d,x,y;
      cin >> c >> d >> x >> y;
      if ( d == 1 ) {

	for ( int i = y; i < y+4; i++ ) {
	  for ( int j = x; j < x+2; j++ ) map[i][j] = c;
	}
      
      } else if ( d == 0 ) {
	for ( int i = y; i < y+2; i++ ) {
	  for ( int j = x; j < x+4; j++ ) map[i][j] = c;
	}
      }
      
    }
    color = map[ys][xs];
    if ( dfs(ys,xs) ) cout << "OK" << endl;
    else cout << "NG" << endl;
    
  }

  return 0;
}

C++: #include <iostream>
using namespace std;
  
int F[105][105];
int xg,yg;
  
  
void DFS(int Y,int X,int c){
  if(F[Y][X] != c){
    return;
  }
  
  F[Y][X] = -2000;
  DFS(Y-1,X  ,c);
  DFS(Y  ,X+1,c);
  DFS(Y+1,X  ,c);
  DFS(Y  ,X-1,c);
}
  
  
int main(){
  int w,h,xs,ys,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;

      
    cin >> xs >> ys >> xg >> yg >> n;
    int c[n],d[n],x[n],y[n],ca;
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
    }
    for(int i=0;i<n;i++){
      if(c[i] == 0){
        ca = 1000;
        break;
      }else if(i == n-1){
        ca = 0;
      }
    }
    for(int i=0; i<102; i++){
          for(int j=0; j<102; j++){
            F[i][j]=ca;
          }
    }
    for(int i=0;i<n;i++){
      if(d[i] == 0){
        for(int j=0;j<4;j++){
          F[x[i]+j][y[i]] = c[i];
          F[x[i]+j][y[i]+1] = c[i];
        }
      } else {
        for(int j=0;j<4;j++){
          F[x[i]][y[i]+j] = c[i];
          F[x[i]+1][y[i]+j] = c[i];
        }
      }
    }
 
  DFS(xs,ys,F[xs][ys]);
  
  if(F[xg][yg] == -2000){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
}