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 <string>
#include <queue>
using namespace std;

typedef pair<int, int> P;


int w, h;
int xs, ys, xg, yg, n, c, d, x, y;
int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};

void put_b(int a[][101]) {
  int X, Y;
  if(d == 0) X = 4, Y = 2;
  else X = 2, Y = 4 ;
  for(int i = 0; i < Y; i++)
    for(int j = 0; j < X; j++)
      a[y + i][x + j] = c;
}

bool bfs(int a[][101]) {
  int cs = a[ys][xs];
  if(cs != a[yg][xg]) return false;
  queue<P> que;
  que.push(P(xs, ys));
  while(que.size()) {
    P p = que.front();
    que.pop();
    if(p.first == xg && p.second == yg) return true;
    for(int i = 0; i < 4; i++) {
      int nx = p.first + dx[i], ny = p.second +dy[i];
      if(0 <= nx && nx < w && 0 <= ny && ny < h && a[ny][nx] == cs) 
	que.push(P(nx, ny));
    }
  }
  return false;
}
int main() {
  while(cin >> w >> h, w != 0 || h != 0) {
    int a[101][101] = {};
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;
  
    while(n--) {
      cin >> c >> d >> x >> y;
      put_b(a);
    }
    /*
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++)
	cout << a[i][j];
      cout << endl;
      }*/
    if(bfs(a) == true) cout << "OK" << endl;
    else cout << "NG" << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<cstring>
#include<queue>
#include<map>
using namespace std;
int C,goal,n,x,y,xs,ys,xg,yg,mas[110][110]={{0}};
int dx[4]={0,0,1,1};
int dy[4]={0,1,0,1};
int d[110][110];
typedef pair<int,int>P;

int bfs();
int main(){

  while(1){
    goal=0;
    memset(mas,0,sizeof(mas));
    memset(d,0,sizeof(d));
    C = goal = n = x = y = xs = ys = xg = yg = 0;
    cin >> x >> y;//ボードの大きさ。 ※：x=横。y=縦。
    if(x==0 && y==0){
      break;
    }
    cin >> xs >> ys;//スタート地点。
    cin >> xg >> yg;//ゴール地点。
    cin >> n;//ブロックの数。
    
    //色染め。
    int color,dire,xx,yy;
    for(int t=0;t<n;t++){
      cin >> color >> dire >> xx >> yy;

      //横長。
      if(dire==0){
	for(int i=0;i<2;i++){
	  for(int j=0;j<4;j++){
	    mas[yy+i][xx+j]=color;
	  }
	}
      }
      
      //縦長。
      else{
	for(int i=0;i<4;i++){
	  for(int j=0;j<2;j++){
	    mas[yy+i][xx+j]=color;
	  }
	}
      }
      
    }
    
    //通る色　摘出。
    C=mas[ys][xs];
    //cout << "color:" << C << endl;
    
    if(C!=0){

      bfs();

    
      if(goal==1){
	cout << "OK" << endl;
      }
      else{
	cout << "NG" << endl;
      }
    }
    else{
      cout << "NG" << endl;
    }
  }
}

int bfs(){
  queue<P>que;
  memset(d,-1,sizeof(d));
  que.push(P(ys,xs));
  d[ys][xs]=0;
  while(!que.empty()){
    P p=que.front();
    que.pop();
    if(p.first==yg && p.second==xg){
      goal=1;
      break;
    }
    for(int i=0;i<4;i++){
      int ny=p.first+dy[i];
      int nx=p.second+dx[i];
      if(ny>=1 && ny<=y && nx>=1 && nx<=x && mas[ny][nx]==C && d[ny][nx]==-1){
	d[ny][nx] = 1;
	que.push(P(ny,nx));
      }
    }
  }
  return (0);
}

C++: #include<iostream>
using namespace std;
#define MAX 100
static const int dx[4] = {1, 0, -1, 0};
static const int dy[4] = {0, -1, 0, 1};

int w, h, sx, sy, gx, gy, G[MAX+2][MAX+2];
 
bool dfs( int x, int y, int color ){
    if ( color == 0 || G[x][y] != color ) return false;
    if ( x == gx && y == gy ) return true;
    G[x][y] = 0;
    for ( int r = 0; r < 4; r++ ){
	if ( dfs(x + dx[r], y + dy[r], color) ) return true;
    }
    return false;
}

main(){
    int n, c, d, px, py, ww, hh;
    while( cin >> w >> h && w ){
	cin >> sx >> sy >> gx >> gy >> n;
	for ( int y = 0; y < h+2; y++ )
	    for ( int x = 0; x < w+2; x++ ) G[x][y] = 0;
	for ( int i = 1; i <=n; i++ ){
	    cin >> c >> d >> px >> py;
	    if ( d == 0 ) { ww = 4; hh = 2; }
	    else { ww = 2; hh = 4; }
	    for ( int y = 0; y <= hh-1; y++ ){
		for ( int x = 0; x <= ww-1; x++ ) {
		    G[px+x][py+y] = c;
		}
	    }
	}
	if ( dfs(sx, sy, G[sx][sy]) ) cout << "OK" << endl;
	else cout << "NG" << endl;
    }
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
int w,h,xs,ys,xg,yg,n;
int c,d,x,y,ans=0,f=0;
int map[100][100]={0},v[100][100]={0};
int root(int x,int y,int vmap[][100]){
	int mx[]={0,1,0,-1},fx;
	int my[]={1,0,-1,0},fy;
	if(x==xg&&y==yg){
		f=1;
		return f;
	}
	for(int i=0;i<4;i++){
		fx=x+mx[i];
		fy=y+my[i];
		if(map[fy][fx]==map[xs][ys]&&fy>=0&&fy<h&&fx>=0&&fx<w&&vmap[fy][fx]==0){
			vmap[fy][fx]=1;
			return root(fx,fy,vmap);
		}
	}
	return f;
}
int main(){
	scanf("%d %d",&w ,&h);
	while(w!=0&&h!=0){
		scanf("%d %d %d %d %d",&xs ,&ys ,&xg ,&yg ,&n);
		for(int i=0;i<n;i++){
			scanf("%d %d %d %d",&c ,&d ,&x ,&y);
			if(d==0){
				for(int w=x;w<x+4;w++){
					for(int h=y;h<y+2;h++){
						map[h][w]=c;
					}
				}
			}
			if(d==1){
				for(int w=x;w<x+2;w++){
					for(int h=y;h<y+4;h++){
						map[h][w]=c;
					}
				}
			}
		}
		/*for(int i=0;i<w;i++){
			for(int i1=0;i1<h;i1++){
				printf("%d ",map[i][i1]);
			}printf("\n");
		}*/
		x=xs;
		y=ys;
		ans=root(x,y,v);
		if(ans==1){
			printf("OK\n");
		}
		else{
			printf("NG\n");
		}
		for(int i=0;i<100;i++){
			for(int i1=0;i1<100;i1++){
				map[i][i1]=0;
				v[i][i1]=0;
			}
		}
		f=0;
		ans=0;
		scanf("%d %d",&w ,&h);
	}
	return 0;
}