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;

char F[102][102];

void DFS(int Y,int X,char C){
	if(F[Y][X]!=C)
		return;

	F[Y][X]='.';
	
	DFS(Y-1,X,C);
	DFS(Y,X+1,C);	
	DFS(Y+1,X,C);
	DFS(Y,X-1,C);

}


int main(){
while(1){
	int w,h;
	cin>>w>>h;
	if(w==0&&h==0)
		break;
	
	int xs,ys,xg,yg;
	cin>>xs>>ys>>xg>>yg;
	int n;
	cin>>
#include<iostream>
using namespace std;

char F[102][102];

void DFS(int Y,int X,char C){
	if(F[Y][X]!=C)
		return;

	F[Y][X]='.';
	
	DFS(Y-1,X,C);
	DFS(Y,X+1,C);	
	DFS(Y+1,X,C);
	DFS(Y,X-1,C);

}


int main(){
while(1){
	int w,h;
	cin>>w>>h;
	if(w==0&&h==0)
		break;
	
	int xs,ys,xg,yg;
	cin>>xs>>ys>>xg>>yg;
	int n;
	cin>>n;
	char C;
	for(int i=0;i<n;i++){
		int d,x,y;
		char c;
		cin>>c;
		cin>>d>>x>>y;
		if(d==0){
			for(int j=0;j<2;j++){
				for(int l=0;l<4;l++){
					F[y+j][x+l]=c;
				}
			}
		}else{
			for(int j=0;j<4;j++){
				for(int l=0;l<2;l++){
					F[y+j][x+l]=c;
				}
			}
		}
	}
	C=F[ys][xs];
	if(C!=0){
		DFS(ys,xs,C);
		if(F[yg][xg]=='.'&&F[ys][xs]=='.'){
			cout<<"OK"<<endl;
		}else{
			cout<<"NG"<<endl;
		}
	}else{
		cout<<"NG"<<endl;
	}
	
	
}
return 0;
}n;
	char C;
	for(int i=0;i<n;i++){
		int d,x,y;
		char c;
		cin>>c;
		cin>>d>>x>>y;
		if(d==0){
			for(int j=0;j<2;j++){
				for(int l=0;l<4;l++){
					F[y+j][x+l]=c;
				}
			}
		}else{
			for(int j=0;j<4;j++){
				for(int l=0;l<2;l++){
					F[y+j][x+l]=c;
				}
			}
		}
	}
	C=F[ys][xs];
	if(C!=0){
		DFS(ys,xs,C);
		if(F[yg][xg]=='.'&&F[ys][xs]=='.'){
			cout<<"OK"<<endl;
		}else{
			cout<<"NG"<<endl;
		}
	}else{
		cout<<"NG"<<endl;
	}
	
	
}
return 0;
}

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

int f[102][102];

void DFS(int x,int y,int c){
    if(f[x][y]!=c)  return;

    f[x][y]=10;
    DFS(x+1,y,c);
    DFS(x-1,y,c);
    DFS(x,y+1,c);
    DFS(x,y-1,c);
}

void print(int w,int h){
    for(int i=1;i<=w;i++){
        for(int j=1;j<=h;j++){
            cout<<f[i][j]<<' ';
        }
        cout<<endl;
    }
}

int main(){
    int w,h;
    int xs,ys;
    int xg,yg;
    int n;
    while(true){
        cin>>w>>h;
        if(w+h==0)  break;
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                f[i][j]=-1;
            }
        }
        cin >> xs >> ys;
        cin >> xg >> yg;
        cin >> n;
        for(int i=0;i<n;i++){
            int c,d,x,y;
            cin >> c >> d >> x >> y;
            if(d==0){
                for(int j = 0; j<4; j++){
                    for(int k = 0; k<2; k++){
                        f[x+j][y+k] = c;
                    }
                }
            }else{
                for(int j = 0; j<2; j++){
                    for(int k = 0; k<4; k++){
                        f[x+j][y+k] = c;
                    }
                }
            }
        }
        //print(w,h);
        DFS(xs,ys,f[xs][ys]);
        print(w,h);
        if(f[xg][yg]==10){
            cout<<"OK"<<endl;
        }else{
            cout<<"NG"<<endl;
        }
    }
    return 0;
}

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


#define rep(i,n) for(short i = 0; i < n; i++)
#define MAX 50

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

typedef pair<short,short> P;
P S,G;
short w,h;

short color;

bool check(short maze[MAX][MAX])
{
	
	queue<P> que;
	que.push(S);
	color = maze[S.second][S.first];

	short nx,ny;
	while(que.size()){
		P p = que.front();	que.pop();

		if(p == G){
			while(que.size())
				que.pop();
			return true;
		}

		rep(i,4){
			nx = p.first + dx[i], ny = p.second + dy[i];
			
			if(nx > -1 && ny > -1 && nx < w && ny < h &&
				maze[ny][nx] == color){
					maze[ny][nx] = -1;
					que.push(P(nx,ny));
			}

		}
	}


	
	return false;
}

int main(void)
{
	short n,c,d,x,y;
	short maze[MAX][MAX];
	while(cin >> w >> h, w){
		cin >> S.first >> S.second;
		cin >> G.first >> G.second;
		S.first = S.first / 2;
		S.second= S.second/ 2;

		cin >> n;

		rep(i,n){
			cin >> c >> d >> x >> y;
			x /= 2;
			y /= 2;
			x++;
			y++;

			if(d == 0)
				maze[y][x] = maze[y][x+1] = c;
			else
				maze[y][x] = maze[y+1][x] = c;
		}
		
		if(maze[S.second][S.first] == maze[G.second][G.first] && check(maze))
			cout << "OK\n";
		else
			cout << "NG\n";
/*
		rep(i,y){
			rep(j,x)
				printf("%2d", maze[i][j]);
			cout << endl;
		}

*/
	}
	
	return 0;
}