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 <bits/stdc++.h>

using namespace std;

#define MAX 101

int H, W, sx, sy, gx, gy;
int color, dir, field[MAX][MAX];

struct P{
  int x, y;
  P(int x, int y) : x(x), y(y) {}
};

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

bool check(int y, int x){
  if(0 <= y && y < H && 0 <= x && x < W){
    return true;
  }
  return false;
}

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

  }
}

bool bfs(){
  bool used[MAX][MAX];
  memset(used, false, sizeof(used));
  used[sy][sx] = true;

  queue<P> Q;
  Q.push(P(sx, sy));

  while(!Q.empty()){
    P p = Q.front(); Q.pop();

    if(field[p.y][p.x] == -1) continue;

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

      if(!check(ny, nx) || used[ny][nx] || 
         field[p.y][p.x] != field[ny][nx]) continue;

      used[ny][nx] = true;
      Q.push(P(nx, ny));     
    }
  }
  return used[gy][gx];
}

int main(){
  int n, x, y;
  while(cin >> W >> H, (W | H)){
    memset(field, -1, sizeof(field));

    cin >> sx >> sy >> gx >> gy >> n;
    sy--, sx--, gy--, gx--;

    for(int i = 0 ; i < n ; i++){
      cin >> color >> dir >> x >> y;
      y--, x--;
      paint(y, x);
    }
    cout << (bfs() ? "OK" : "NG") << endl;
  }

  return 0;
}

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

int dx[4] = { 1, 0, -1, 0 };
int dy[4] = { 0, 1, 0, -1 };


class cordinate
{

public:
	int x;
	int y;

};

int main()
{
	while(1)
	{


		int w;
		int h;
		cin >> w >> h; 
		if(w == 0 && h == 0)
		{
			break;
		}
		int xs;
		int ys;
		cin >> xs >> ys;
		int xg;
		int yg;
		cin >> xg >> yg;
		int n;
		cin >> n;

		vector<vector<int >> vobj;

		for(int i = 0; i < h; i++)
		{
			vector<int> lineobj;
			for(int j = 0; j < w; j++)
			{

				lineobj.push_back(0);

			}
			vobj.push_back(lineobj);

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

			if(d == 0)
			{
				vobj[x][y] = c;
				vobj[x + 1][y] = c;
				vobj[x + 2][y] = c;
				vobj[x + 3][y] = c;
				vobj[x][y + 1] = c;
				vobj[x + 1][y + 1] = c;
				vobj[x + 2][y + 1] = c;
				vobj[x + 3][y + 1] = c;
			}
			else if(d == 1)
			{
				vobj[x][y] = c;
				vobj[x][y + 1] = c;
				vobj[x][y + 2] = c;
				vobj[x][y + 3] = c;
				vobj[x + 1][y] = c;
				vobj[x + 1][y + 1] = c;
				vobj[x + 1][y + 2] = c;
				vobj[x + 1][y + 3] = c;
			}
		}

		int startColor;
		startColor = vobj[xs - 1][ys - 1];
		queue<cordinate> que;

		cordinate obj;
		obj.x = xs - 1;
		obj.y = ys - 1;
		que.push(obj);
		bool flag = false;
		while(1)
		{
			if(startColor == 0)
			{
				break;
			}
			cordinate buf;
			buf = que.front();
			que.pop();

			int bx;
			int by;
			bx = buf.x;
			by = buf.y;
			if(bx == xg - 1 && by == yg - 1)
			{
				flag = true;
				break;
			}
			for(int i = 0; i < 4; i++)
			{
				if(bx + dx[i] >= 0 && bx + dx[i] <= w - 1)
				{
					if(by + dy[i] >= 0 && by + dy[i] <= h - 1)
					{
						if(vobj[bx + dx[i]][by + dy[i]] == startColor)
						{
							cordinate newObject;
							newObject.x = bx + dx[i];
							newObject.y = by + dy[i];
							que.push(newObject);

						}
					}
				}
			}
			vobj[bx][by] = -1;

			if(que.size() == 0)
			{
				break;
			}
		}


		if(flag == true)
		{
			cout << "OK" << endl;
		}
		else{
			cout << "NG" << endl;
		}
		/*for(int i = 0; i < w - 1; i++)
		{
			for(int j = 0; j < h - 1; j++)
			{
				cout << vobj[i][j] << " ";
			}
			cout << endl;
		}  */

	}



}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int a[100][100];
bool l=false;
void solve(int n, int m, int xg, int yg, int c,int h,int w) {
	if (m + 1 < w&&a[n][m + 1] == c) {
		a[n][m + 1] = 1000;
		if (n == xg&&m+1 == yg) {
			l = true; return;
		}
		solve(n, m+1, xg, yg, c, h, w);
	}
	if (m - 1 >= 0 && a[n][m - 1] == c) {
		a[n][m - 1] = 1000;
		if (n == xg&&m - 1 == yg) {
			l = true; return;
		}
		solve(n, m-1, xg, yg, c, h, w);
	}
	if (n + 1 < h && a[n+1][m] == c) {
		a[n+1][m] = 1000;
		if (n+1 == xg&&m == yg) {
			l = true; return;
		}
		solve(n+1, m, xg, yg, c, h, w);
	}
	if (n - 1 >= 0 && a[n-1][m] == c) {
		a[n-1][m] = 1000;
		if (n-1 == xg&&m  == yg) {
			l = true; return;
		}
		solve(n-1, m, xg, yg, c, h, w);
	}
}
int main() {
	int w, h;
	while (cin >> w >> h&&w != 0 && h != 0) {
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++)
				a[i][j] = 0;
		}
		int xs, ys, xg, yg,n;
		cin >> ys >> xs;
		cin >> yg >> xg;
		xs--; ys--; xg--; yg--;
		cin >> n;
		for (int i = 0; i < n; i++) {
			int c, d, x, y;
			cin >> c >> d >> y >> x;
			x--;
			y--;
			if (d == 0) {
				for (int j = 0; j < 2; j++) {
					for (int z = 0; z < 4; z++) 
						a[x + j][y + z] = c;
				}
			}
			else {
				for (int j = 0; j < 4; j++) {
					for (int z = 0; z < 2; z++)
						a[x + j][y + z] = c;
				}
			}
		}
		int k = a[xs][ys];
		a[xs][ys] = 1000;
		l = false;
		solve(xs, ys, xg, yg, k,h,w);
		if (l) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}