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>
#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(ans == 1) return ;
    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);
    }
    return;
}

int main()
{
    while(cin >> w >> h )
    {
        if(w==0 && h==0) break;
        memset(block,0,sizeof(block));
        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];
        if(c==0) {cout <<"NG" << endl; continue;}
        
        //cout << xs << " " << ys << " " << c << endl;
        //cout <<"input " << endl;
        solve(xs,ys);

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

    }

    return 0;
}

C++: #include <set>
#include <map>
#include <list>
#include <queue>
#include <stack>
#include <cmath>
#include <ctype.h>
#include <ctime>
#include <cstdio>
#include <vector>
#include <string>
#include <bitset>
#include <cctype>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <numeric>
#include <complex>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <cassert>
#include <iostream>
#include <iterator>
#include <algorithm>

using namespace std;
#define  MAX 100
int dx[] = {0,1,0,-1};
int dy[] = {-1,0,1,0};
int field[MAX][MAX]; 
int w,h;
int xs,ys,xg,yg;
int n;
int color;
bool flag = false;

void blockset(int a,int b,int xx,int yy){
	if(b == 0){
		field[yy][xx] = a;	
		field[yy][xx+1] = a;	
		field[yy][xx+2] = a;	
		field[yy][xx+3] = a;	
		field[yy+1][xx] = a;	
		field[yy+1][xx+1] = a;	
		field[yy+1][xx+2] = a;	
		field[yy+1][xx+3] = a;	
	}else if(b == 1){
		field[yy][xx] = a;	
		field[yy+1][xx] = a;	
		field[yy+2][xx] = a;	
		field[yy+3][xx] = a;	
		field[yy][xx+1] = a;	
		field[yy+1][xx+1] = a;	
		field[yy+2][xx+1] = a;	
		field[yy+3][xx+1] = a;
	}
}

void dfs(int x,int y){
	field[y][x] = 0;
	
	if(x == xg && y == yg){
		flag = true;
		return;
	}
	for(int i = 0;i < 4;i++){
		int nx = x + dx[i];
		int ny = y + dy[i];
		if(nx < 0 || ny < 0 || nx >= w || ny >= h){
			continue;
		}else if(field[ny][nx] == color){
			dfs(nx,ny);
		} 
	}
	
	
}

int main(){
	while(true){
		cin >> w >> h;
		if(w == 0 && h == 0) break;
		cin >> xs >> ys >> xg >> yg;
		xs--;
		ys--;
		xg--;
		yg--;
		cin >> n;
		for(int i = 0;i < n;i++){
			int c,d,x,y;
			cin >> c >> d >> x >> y;
			x--;
			y--;
			blockset(c,d,x,y);
		}
		color = field[ys][xs];
		flag = false;
		if(color)dfs(xs,ys);

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

	return 0;
}