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<stdio.h>

#include<queue>
#include<iostream>

using namespace std;

enum
{
	wide, high,
	none = 0
};

#define BLOCK_WIDE 2
#define BLOCK_HIGH 4

void HighBlock(char map[100 +2][100 +2] ,int color, int x, int y)
{
	int i = y, j;
	y += BLOCK_HIGH;
	while (i < y)
	{
		j = x;
		while (j < x + BLOCK_WIDE)
		{
			map[i][j++] = color;
		}

		++i;
	}
}

void WideBlock(char map[100 +2][100 +2] ,int color, int x, int y)
{
	int i = y, j;
	y += BLOCK_WIDE;
	while (i < y)
	{
		j = x;
		while (j < x + BLOCK_HIGH)
		{
			map[i][j++] = color;
		}

		++i;
	}
}

int sx, sy;
int gx, gy;
int n;

#define X first
#define Y second

void func(char map[100 + 2][100 + 2])
{
	int mx[] = { 0 ,1 ,-1 ,0 };
	int my[] = { 1 ,0 ,0 ,-1 };
	int way = map[sy][sx];
	queue< pair< int, int > > que;
	que.push(make_pair(sx, sy));

	while (!que.empty())
	{
		pair<int, int> top = que.front(); que.pop();

		int x = top.X, y = top.Y;
		if (map[y][x] == way)
		{
			if (x == gx && y == gy)
			{
				puts("OK");
				return;
			}

			map[y][x] = none;

			int i = 4;
			while (i--)
			{
				int xx = x + mx[i];
				int yy = y + my[i];

				if (map[yy][xx] == way)
				{
					que.push(make_pair(xx, yy));
				}
			}
		}
	}

	puts("NG");
}

int main(void)
{
	char map[100 + 2][100 + 2];
	int W, H;
	while (1)
	{
		scanf("%d %d", &W, &H);

		if ((W | H) == 0)
		{
			return 0;
		}

		scanf("%d %d", &sx, &sy);
		scanf("%d %d", &gx, &gy);
		scanf("%d", &n);

		int i;
		for (i = 0; i < n; ++i)
		{
			int color, d, x, y;
			scanf("%d %d %d %d", &color, &d, &x, &y);

			if (d == wide)
			{
				WideBlock(map, color, x, y);
			}

			if (d == high)
			{
				HighBlock(map, color, x, y);
			}
		}

		func(map);
	}
}

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));
    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[1][1];
    
    bfs();
    
    if(goal==1){
      cout << "OK" << 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(mas[ny][nx]==C && ny>=1 && ny<=y && nx>=1 && nx<=x && d[ny][nx]==-1){
	que.push(P(ny,nx));
	d[ny][nx]=d[p.first][p.second]+1;
      }
    }
  }
  return (0);
}

C++: #include <bits/stdc++.h>
using namespace std;
const int limit = 100;
int w, h, n;
int xs, ys, xg, yg;
int maze[limit][limit];
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};
int flag = 0;

void dfs(int x, int y){
    maze[x][y] = 0;
    //4近傍を探索
    for(int i=0; i < 4; i++){
            int nx = x + dx[i], ny = y + dy[i];
            if(0 <= nx and nx < h and 0 <= ny and ny < w and maze[nx][ny] != 0){
                if(nx == (xg-1) and ny == (yg-1)) flag = 1;
                dfs(nx, ny);
            }
        }
    return;
}


int main(){
    while(1){
    flag = 0;
    cin >> w >> h;
    if(w == 0 and h == 0) break;
    cin >> xs >> ys >> xg >> yg >> n;
    //ボードを初期化
    for(int i=0; i < w; i++)for(int j=0; j < h; j++) maze[i][j] = 0;
    //ボードにブロックを敷き詰める
    for(int i=0; i < n; i++){
        int c = 0, d = 0, x = 0, y = 0;
        cin >> c >> d >> x >> y;
        if(d)for(int dx=0; dx < 2; dx++)for(int dy=0; dy < 4; dy++) maze[x-1+dx][y-1+dy] = c;
        else for(int dy=0; dy < 2; dy++)for(int dx=0; dx < 4; dx++) maze[x-1+dx][y-1+dy] = c;
    }
    //迷路を単純化する
    for(int i=0; i < w; i++)for(int j=0; j < h; j++) if(maze[i][j] != maze[xs-1][ys-1]) maze[i][j] = 0;

    //search
    dfs(xs-1, ys-1);
    if(flag) cout << "OK" << endl;
    else cout << "NG" << endl;
    }
    return 0;
}

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

struct board{
  int mass[102][102];
};

bool goal_flag;
void DFS(int x,int y,int gx,int gy,board b,int c){
    if(b.mass[y][x]!=c)return;
    if(!b.mass[y][x])return;
    b.mass[y][x]=0;
    if(x==gx&&y==gy)goal_flag=true;
    DFS(x+1,y,gx,gy,b,c);
    DFS(x-1,y,gx,gy,b,c);
    DFS(x,y+1,gx,gy,b,c);
    DFS(x,y-1,gx,gy,b,c);
}

int main(){
  int h,w;
  int start_x,start_y;
  int goal_x,goal_y;
  int n;
  int c,d,x,y;
  while(1){
    cin>>w>>h;
    if(w==0&&h==0)break;
    cin>>start_x>>start_y;
    cin>>goal_x>>goal_y;
    cin>>n;

    board b;
    for(int i=0;i<h+2;i++){
      for(int j=0;j<w+2;j++){
        b.mass[i][j]=0;
      }
    }

    for(int i=0;i<n;i++){
        cin>>c>>d>>x>>y;
        for(int j=0;j<2;j++){
          for(int k=0;k<4;k++){
            if(d==0){b.mass[y+j][x+k]=c;}
            else if(d==1){b.mass[y+k][x+j]=c;}
          }
        }
    }
    goal_flag=false;
    DFS(start_x,start_y,goal_x,goal_y,b,b.mass[start_y][start_x]);
    if(goal_flag)cout<<"OK";
    else cout<<"NG";
    cout<<endl;
  }
}