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(Color==0){
                        cout<<"NG"<<endl;
                        break;
                }
                if(recursion(Start.y,Start.x)>0)
                        cout <<"OK"<<endl;
                else
                        cout <<"NG"<<endl;
        }
        return 0;
}

C++: #include <cmath>
#include <ctime>
#include <algorithm>
#include <iostream>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <list>
#include <deque>
#include <stack>
#include <bitset>
#include <functional>
#include <numeric>
#include <utility>
#include <iomanip>
#include <cstdio>
#include <cctype>
#include <queue>
#include <complex>
#include <climits>

typedef long long ll;

using namespace std;

int maze[110][110];
int f[110][110];
int w, h, xs, ys, xg, yg, res = 0;
int color;

void dfs(int cx, int cy){
	if(f[cx][cy]) return ;
	f[cx][cy] = 1;
	if(cx == xg && cy == yg){
		res = 1;
		return ;
	}
	for(int dx=-1; dx<=1; ++dx){
		for(int dy=-1; dy<=1; ++dy){
			if(abs(dx-dy) != 1) continue;
			int nx = cx + dx, ny = cy + dy;
			if(maze[nx][ny] == color){
				dfs(nx, ny);
			}
		}
	}
	return ;
}


int main(void){
	int n;
	while(cin >> w >> h){
		res = 0;
		if(w == 0 && h == 0) break;
		cin >> xs >> ys >> xg >> yg >> n;
		for(int i=0; i<110; ++i){
			for(int j=0; j<110; ++j){
				maze[i][j] = 6;
				f[i][j] = 6;
			}
		}
		for(int i=1; i<=h; ++i){
			for(int j=1; j<=w; ++j){
				maze[i][j] = 0;
				f[i][j] = 0;
			}
		}

		for(int i=0; i<n; ++i){
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			if(d == 0){
				for(int j=y; j<=y+1; ++j){
					for(int k=x; k<=x+3; ++k){
						maze[j][k] = c;
					}
				}
			}
			if(d == 1){
				for(int j=y; j<=y+3; ++j){
					for(int k=x; k<=x+1; ++k){
						maze[j][k] = c;
					}
				}
			}
		}

		color = maze[xs][ys];
		if(color == 0){
			cout << "NG" << endl;
			continue;
		}

		dfs(xs, ys);

		if(res){
			cout << "OK" << endl;
		} else {
			cout << "NG" << endl;
		}
	}

	return 0;
}

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

int w,h;
int field[104][104];
int gx,gy;
int sc;

void init()
{
	for(int i=0;i<104;i++){
		for(int j=0;j<104;j++){
			field[i][j] = 0;
		}
	}
}
bool search(int x,int y)
{
	bool flag = false;
	if(x == gx && y == gy)
		flag = true;
	else{
		int vectorx[4] = {-1,0,1,0},vectory[4] = {0,-1,0,1};
		for(int i=0;i<4;i++){
			if(x+vectorx[i] >= 0 && y+vectory[i] >= 0 && x+vectorx[i] < w && y+vectory[i] < h){
				if(field[x+vectorx[i]][y+vectory[i]] == sc){
					field[x][y] = -1;
					flag |= search(x+vectorx[i],y+vectory[i]);
				}
			}
		}
	}
	return flag;
}
int main()
{
	while(cin >> w >> h){
		if(w == 0 && h == 0)
			break;
		init();
		int sx,sy;
		cin >> sx >> sy;
		cin >> gx >> gy;
		int n,c,x,y;
		bool d;
		cin >> n;
		for(int i=0;i<n;i++){
			cin >> c >> d >> x >> y;
			int vectorx,vectory;
			if(d == 0){
				vectorx = 4;vectory = 2;
			}else{
				vectorx = 2;vectory = 4;
			}
			for(int j=0;j<vectorx;j++){
				for(int k=0;k<vectory;k++){
					field[x+j][y+k] = c;
				}
			}
		}
		sc = field[sx][sy];
		if(field[sx][sy] == 0 || field[gx][gy] == 0)
			cout << "NG" << endl;
		else{
			if(search(sx,sy))
				cout << "OK" << endl;
			else
				cout << "NG" << endl;
		}
	}
	return 0;
}