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;
struct cordinate{
        int y;
        int x;
};
cordinate SIZE,Start,Goal;
struct Blocks{
        int color;
        int direction;
        int y;
        int x;
};
Blocks block[200];
int N,board[200][200];
int Color,dp[200][200];
int recursion(int y,int x){
        int res=0;
        if(y==Goal.y && x==Goal.x){
                res=1;
        }
        else if(dp[y][x]!=-1)
                return dp[y][x];
        else{
                dp[y][x]=0;
                if(board[y+1][x]==Color && dp[y+1][x]==-1)
                        res+=recursion(y+1,x);
                if(board[y-1][x]==Color && dp[y-1][x]==-1)
                        res+=recursion(y-1,x);
                if(board[y][x+1]==Color && dp[y][x+1]==-1)
                        res+=recursion(y,x+1);
                if(board[y][x-1]==Color && dp[y][x-1]==-1)
                        res+=recursion(y,x-1);
        }
        return dp[y][x]=res;
}
int main(){
        while(true){
                for(int i=0 ; i<100 ; i++ )
                        for(int j=0 ; j<100 ; j++ ){
                                dp[i][j]=-1;
                                board[i][j]=0;
                        }
                cin >> SIZE.x >> SIZE.y;
                if(SIZE.x+SIZE.y==0)
                        break;
                cin >> Start.x >> Start.y;
                cin >> Goal.x >> Goal.y;
                cin >> N;
                for(int i=0 ; i<N ; i++ ){
                        cin >> block[i].color >> block[i].direction;
                        cin >> block[i].x >> block[i].y;
                        if(block[i].direction){
                                for(int l=block[i].y ; l<block[i].y+4 ; l++ ){
                                        for(int j=block[i].x ; j<block[i].x+2 ; j++ ){
                                                board[l][j]=block[i].color;
                                        }
                                }
                        }
                        else{
                                for(int l=block[i].y ; l<block[i].y+2 ; l++ ){
                                        for(int j=block[i].x ; j<block[i].x+4 ; j++ ){
                                                board[l][j]=block[i].color;
                                        }
                                }
                        }
                }
                Color=board[Start.y][Start.x];
                if(recursion(Start.y,Start.x)>0)
                        cout <<"OK"<<endl;
                else
                        cout <<"NG"<<endl;
        }
        return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <complex>
#include <string>
#include <sstream>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <functional>
#include <iostream>
#include <map>
using namespace std;
typedef pair<int,int> P;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-9
#define INF 2000000000
#define sz(x) ((int)(x).size())
#define fi first
#define sec second
#define SORT(x) sort((x).begin(),(x).end())
#define all(x) (x).begin(),(x).end()
#define EQ(a,b) (abs((a)-(b))<eps)
int w,h;
int sx,sy,gx,gy;
int n;
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};
bool used[120][120];
int f[120][120];
void set(int c,int d,int x,int y)
{
	if(d==0)
	{
		for(int i=0;i<2;i++)
		{
			for(int j=0;j<4;j++)
			{
				f[x+i][y+j]=c;
			}
		}
	}
	else
	{
		for(int i=0;i<4;i++)
		{
			for(int j=0;j<2;j++)
			{
				f[x+i][y+j]=c;
			}
		}
	}
	return;
}
bool judge()
{
	if(f[sx][sy]!=f[gx][gy])return false;
	memset(used,false,sizeof(used));
	queue<P> q;
	q.push(mp(sx,sy));
	used[sx][sy]=true;
	while(!q.empty())
	{
		P a=q.front();
		q.pop();
		for(int i=0;i<4;i++)
		{
			int nx=a.fi+dx[i],ny=a.sec+dy[i];
			if(nx<0||nx>=w||ny<0||ny>=h)continue;
			if(used[nx][ny]||f[nx][ny]!=f[a.fi][a.sec])continue;
			if(nx==gx&&ny==gy)return true;
			used[nx][ny]=true;
			q.push(mp(nx,ny));
		}
	}
	return false;
}
int main()
{
	while(1)
	{
		memset(f,0,sizeof(f));
		scanf("%d %d",&h,&w);
		if(w==0&&h==0)break;
		scanf("%d %d",&sy,&sx);
		scanf("%d %d",&gy,&gx);
		scanf("%d",&n);
		for(int i=0;i<n;i++)
		{
			int c,d,x,y;
			scanf("%d %d %d %d",&c,&d,&y,&x);
			set(c,d,x,y);
		}
		if(judge())puts("OK");
		else puts("NG");
	}
	return 0;
}

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

int F[102][102] = { 0 };

void DFS(int Y, int X, int c) {
	//cout << Y << " " << X << endl;
	if (F[Y][X] != c)
		return;
	F[Y][X] = 10;
	DFS(Y - 1, X, c);//???
					 //DFS(Y - 1, X+1, A_ito);//??????
	DFS(Y, X + 1, c);//???
					 //DFS(Y + 1, X+1, A_ito);//??????
	DFS(Y + 1, X, c);//???
					 //DFS(Y + 1, X-1, A_ito);//??????
	DFS(Y, X - 1, c);//???
					 //DFS(Y - 1, X-1, A_ito);//??????
}


int main()
{
	int xs, ys, xg, yg, n;
	int c, d, x, y;
	int W = 1, H = 1;

	while (true) {
		cin >> W >> H;
		if ((W == 0) && (H == 0)) {
			break;
		}
		cin >> xs >> ys >> xg >> yg >> n;
		for (int i = 1;i <= n;i++) {
			cin >> c >> d >> x >> y;
			if (d == 0) {
				F[x][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y] = c;
				F[x + 1][y + 1] = c;
				F[x + 2][y] = c;
				F[x + 2][y + 1] = c;
				F[x + 3][y] = c;
				F[x + 3][y + 1] = c;
			}
			if (d == 1) {
				F[x][y] = c;
				F[x + 1][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y + 1] = c;
				F[x][y + 2] = c;
				F[x + 1][y + 2] = c;
				F[x][y + 3] = c;
				F[x + 1][y + 3] = c;
			}
		}
		if (F[ys][xs] != 0)
			DFS(ys, xs, F[ys][xs]);

		if (F[yg][xg] == 10) {
			cout << "OK" << endl;
		}
		else { cout << "NG" << endl; }
		for (int i = 0;i < H;i++) {
			for (int j = 0;j < W;j++) {
				F[i][j] = 0;
			}
		}

	}

	return 0;
}