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>
using namespace std;

int F[102][102];

void DFS(int Y,int X,int C){
   if(F[Y][X]!=C)
      return;
   F[Y][X]=6;
   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,xg,yg,n;
   int c,d,x,y;
   while(true){
      cin >> w >> h;
      if(w==0&&h==0)
         break;
      cin >> xs >> ys;
      cin >> xg >> yg;
      cin >> n;
      for(int i=1;i<=n;i++){
         cin >> c >> d >> x >> y;
         if(d==0){
             F[y+1][x+1]=c;
             F[y+1][x+2]=c;
             F[y+1][x+3]=c;
             F[y+1][x+4]=c;  
             F[y+2][x+1]=c;
             F[y+2][x+2]=c;
             F[y+2][x+3]=c;
             F[y+2][x+4]=c;   
         }
         else{
             F[y+1][x+1]=c;
             F[y+2][x+1]=c;
             F[y+3][x+1]=c;
             F[y+4][x+1]=c;  
             F[y+1][x+2]=c;
             F[y+2][x+2]=c;
             F[y+3][x+2]=c;
             F[y+4][x+2]=c;   
         }
      }
      if(F[ys+1][xs+1]==1&&F[ys+1][xs+1]==2&&F[ys+1][xs+1]==3&&F[ys+1][xs+1]==4&&F[ys+1][xs+1]==5)
         DFS(ys+1,xs+1,F[ys+1][xs+1]);
      if(F[yg+1][xg+1]==F[ys+1][xs+1])
         cout << "OK" << endl;
      else
         cout << "NG" << endl;
      /*for(int i=1;i<=w;i++)
         for(int j=1;j<=h;j++)
            F[i][j]=0;*/
      
   }
   return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
using namespace std;
 
#define Y first
#define X second

#define max_size 100+10

int my[4] = {0,0,1,-1};
int mx[4] = {1,-1,0,0};

pair<int, int>now,tmp;

void chek(int map[max_size][max_size], int w, int h)
{
	int i, j;
	for(i=0;i<=h+1;i++)
	{
		for (j = 0; j <= w + 1; j++)
		{
			cout << map[i][j];
		}
		cout << endl;
	}
}


int main(void)
{
	int w, h;
	int xs, ys, xg, yg;
	int n;
	int col, d, set_x, set_y;

	int i, j,k;

	while ((cin >> w >> h), w != 0 && h != 0)
	{
		queue< pair<int, int> > QU;

		int map[max_size][max_size] = { 0 };

		cin >> xs >> ys >> xg >> yg >> n;

		for (i = 0; i < n; i++)
		{
			cin >> col >> d >> set_x >> set_y;
			if (d == 0)
			{
				for (j = 0; j < 2; j++)
				{
					for (k = 0; k < 4; k++)
					{
						map[set_y][set_x] = col;
						set_x++;
					}
					set_x -= 4;
					set_y++;
				}
			}
			else
			{
				for (j = 0; j < 4; j++)
				{
					for (k = 0; k < 2; k++)
					{
						map[set_y][set_x] = col;
						set_x++;
					}
					set_x -= 2;
					set_y++;
				}
			}
		}

		//chek(map, w, h);

		if (map[ys][xs] == 0)
		{
			cout << "NG\n";
			continue;
		}

		int s_col = map[ys][xs];

		now.Y = ys;
		now.X = xs;
		QU.push(now);

		bool goal = false;
		while (!QU.empty())
		{
			now = QU.front();
			QU.pop();

			if (map[now.Y][now.X] != -1)
			{
				map[now.Y][now.X] = -1;

				if (now.Y == yg && now.X == xg)
				{
					goal = true;
					while (!QU.empty())
					{
						QU.pop();
					}

					break;
				}

				for (i = 0; i < 4; i++)
				{
					if (map[now.Y + my[i]][now.X + mx[i]]== s_col)
					{
						tmp.Y = now.Y + my[i];
						tmp.X = now.X + mx[i];

						QU.push(tmp);
					}
				}
			}
		}

		if (goal)
		{
			cout << "OK\n";
		}
		else
		{
			cout << "NG\n";
		}

	}
	return 0;
}

C++: 
#include<iostream>
#include<string>
#include<algorithm>
#include<list>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<numeric>
#include<vector>
#include<cstdio>
#include<climits>
#include<cfloat>
#include<cstring>
#define foreach(t,p,it) for(t::iterator it=p.begin(),it!=p.end(),++it)
#define all(p) p.begin(),p.end()
#define rep(i,n) for(int i=0;i<n;i++)
#define REP(n) rep(i,n)
using namespace std;

const int W=210,H = 210;
int block[W][H];
int ans;

int w,h,xs,ys,xg,yg,n,c,d,x,y;
void solve(int xi,int yi)
{
    if(xi==xg && yi==yg){ ans = 1; return;}
    if(block[xi][yi] == c)
    {
        block[xi][yi] = 0;
        solve(xi-1, yi);
        solve(xi, yi-1);
        solve(xi+1, yi);
        solve(xi, yi+1);
    }
    block[xi][yi] = 0;
    return;
}

int main()
{
    while(cin >> w >> h )
    {
        if(w==0 && h==0) break;
        memset(block,0,sizeof(int)*w*h);
        ans = 0;
        cin >> xs >> ys;
        cin >> xg >> yg;
        cin >> n;
        REP(n)
        {
            cin >> c >> d >> x >> y;
            //cout << x << ","<< y << endl;
            if(d==1) //tate
            {
                block[x][y] = c;
                block[x][y+1] =c;
                block[x][y+2] = c;
                block[x][y+3] = c;
                block[x+1][y] = c;
                block[x+1][y+1] = c;
                block[x+1][y+2] = c;
                block[x+1][y+3] = c;
            }
            else
            {
                block[x][y] = c;
                block[x+1][y] = c;
                block[x+2][y] = c;
                block[x+3][y] = c;
                block[x][y+1] = c;
                block[x+1][y+1] = c;
                block[x+2][y+1] = c;
                block[x+3][y+1] = c;
            }
        }
        c = block[xs][ys];
        solve(xs,ys);

        if(ans) cout << "OK" << endl;
        else cout << "NG" << endl;

    }

    return 0;
}