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<stack>
#include<string.h>
using namespace std;
struct ST {
	int a;
	int b;
	int c;
};
long long brock[1000][1000];
long long ds[1000][1000];
int q[4]={0,-1,0,1};
int p[4]={1,0,-1,0};
int main(){
	stack <ST> S;
	ST ma;
	ST ba;
	int w,h;//???????????§??????
	int xs,ys;//??????????????§?¨?
	int xg,yg;//??´????????§?¨?
	int n;//????????????????????°
	int c,d,x,y;//????????????????????±
	int i,j,m,check=0;
	while(1){
		memset(ds,0,sizeof(ds));
		memset(brock,0,sizeof(brock));
		cin>>w>>h;//???????????§????????\???
		if(w==0&&h==0){
			break;
		}
		cin>>xs>>ys>>xg>>yg;//??????????????¨??´???????????§?¨???\???
		cin>>n;//????????????????????°
		for(i=0;i<n;i++){
			cin>>c>>d>>x>>y;
			if(d==1){//???
				for(m=0;m<2;m++){
					for(j=0;j<4;j++){
						brock[x+m][y+j]=c;
					}
				}
			}
			else{//?¨?
				for(m=0;m<4;m++){
					for(j=0;j<2;j++){
						brock[x+m][y+j]=c;
					}
				}
			}
		}
		if(brock[xs][ys]!=brock[xg][yg]){
			cout<<"NG"<<endl;
		}
		else{
			ma.a=xs;
			ma.b=ys;
			ma.c=brock[xs][ys];
			ds[xs][ys]=1;
			S.push(ma);
			check=0;
			while(!S.empty()){
				ba=S.top();
				S.pop();
				ds[ba.a][ba.b]=1;
				if(ba.a==xg&&ba.b==yg){
					check=1;
					break;
				}
				if(ba.c==brock[xg][yg]){
					for(i=0;i<4;i++){
						if(ba.a+p[i]>0&&ba.a+p[i]<=w&&ba.b+q[i]>0&&ba.b+q[i]<=h&&ds[ba.a+p[i]][ba.b+q[i]]==0){
							ma.a=ba.a+p[i];
							ma.b=ba.b+q[i];
							ma.c=brock[ba.a+p[i]][ba.b+q[i]];
							S.push(ma);
						}
					}
				}
			}
			if(check==1){
				cout<<"OK"<<endl;
			}
			else{
				cout<<"NG"<<endl;
			}
		}
	}
	return 0;
}

C++: #include <iostream>
#include <cstring>
#include <deque>
#include <algorithm>

using namespace std;

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

int main(void){
	int w,h;
	
	while(cin >> w >> h){
		if((w|h) == 0) break;
		int f[w+2][h+2], sx, sy, ex, ey;
		bool reachable[w+2][h+2];
		memset(f,-1,sizeof(f));
		memset(reachable, false, sizeof(reachable));
		
		cin >> sx >> sy;
		cin >> ex >> ey;
		
		int n;
		cin >> n;
		int color,d,px,py, hh, ww;
		for(int i=0;i<n;i++){
			cin >> color >> d >> px >> py;
			if(d == 0){
				hh=2;
				ww=4;
			}else{
				hh=4;
				ww=2;
			}
			for(int p=0;p<hh;p++){
				for(int q=0;q<ww;q++){
					f[px+q][py+p] = color;
				}
			}
		}
		
		deque<pair<int,int> > q;
		reachable[sx][sy] = true;
		q.push_back(make_pair(sx,sy));
		
		while(!q.empty()){
			pair<int,int> pii = q.front();
			q.pop_front();
			reachable[pii.first][pii.second] = true;
			for(int i=0;i<4;i++){
				if(f[pii.first][pii.second] == f[pii.first+dx[i]][pii.second+dy[i]] &&
				reachable[pii.first+dx[i]][pii.second+dy[i]] == false){
					reachable[pii.first+dx[i]][pii.second+dy[i]] = true;
					q.push_back(make_pair(pii.first+dx[i], pii.second+dy[i]));
				}
			}
		}
		
		if(reachable[ex][ey]){
			cout << "OK" << endl;
		}else{
			cout << "NG" << endl;
		}
	}
}

C++: #define _USE_MATH_DEFINES
#define INF 10000000
#include <iostream>
#include <sstream>
#include <cmath>
#include <algorithm>
#include <queue>
#include <stack>
#include <limits>
#include <map>
#include <string>
#include <cstring>
#include <set>
#include <deque>
#include <bitset>
#include <list>

using namespace std;

typedef long long ll;
typedef pair<int,int> P;

static const double eps = 1e-8;

int moveTo[][2] = {{-1,0},{1,0},{0,-1},{0,1}};

int stage[100][100];

void paint(int c,int d,int x,int y){
	//c:1~5 d: 0:horizonal 1:vertical
	if(d==0){
		for(int i=x;i<x+4;i++){
			for(int j=y;j<y+2;j++){
				stage[j][i] = c;
			}
		}
	}
	else{
		for(int i=x;i<x+2;i++){
			for(int j=y;j<y+4;j++){
				stage[j][i] = c;
			}
		}
	}
}

bool bfs(int w, int h, int xs, int ys, int xg, int yg){
	int cs = stage[ys][xs];
	int cg = stage[yg][xg];
	if(cs != cg) return false;

	queue<P> que;
	que.push(P(ys,xs));

	while(!que.empty()){
		int sx = que.front().first;
		int sy = que.front().second;
		
		if(sx == xg && sy == yg) return true;
		que.pop();

		stage[sy][sx] = -1;

		for(int i=0;i<4;i++){
			int dx = sx + moveTo[i][0];
			int dy = sy + moveTo[i][1];

			if(dx < 0 || dx >= w || dy < 0 || dy >= h) continue;
			if(stage[dy][dx] != cs || stage[dy][dx] == -1) continue;
			que.push(P(dx,dy));

		}

	}
	return false;
}

int main(){
	int w,h;
	while(~scanf("%d %d",&w,&h)){
		if(w==h && h==0) break;
		memset(stage,-1,sizeof(stage));
		int xs,ys;
		scanf("%d %d",&xs,&ys);

		int xg,yg;
		scanf("%d %d",&xg,&yg);

		int n;
		scanf("%d",&n);
		for(int i=0;i<n;i++){
			int c,d,x,y;
			//c:1~5 d: 0:horizonal 1:vertical
			scanf("%d %d %d %d",&c,&d,&x,&y);
			paint(c,d,x,y);
		}

		printf("%s\n",bfs(w,h,xs,ys,xg,yg) ? "OK" : "NG");
	}
}