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 <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 maze[MAX][MAX];
short color;

bool check()
{
	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;

	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())
			cout << "OK\n";
		else
			cout << "NG\n";

	}
	
	return 0;
}

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

int w,h;
int sx,sy,gx,gy;
int n,c,d,x,y;
int g[200][200];
bool use[200][200];
int dy[] = {-1,-1,0,1,1,1,0,-1}, dx[] = {0,1,1,1,0,-1,-1,-1};

void rec(int Y,int X, char c){
  if(use[Y][X])return;
  use[Y][X] = true;

  for(int i=0;i<8;i++){
    int ny = Y+dy[i], nx = X+dx[i];
    if(ny<1 || nx<1 || ny>h || nx>w)continue;
    if(g[ny][nx] == c)rec(ny,nx,c);
  }
}

int main(){
  while(cin >> w >> h,w||h){
    for(int i=1;i<=h;i++){
      for(int j=1;j<=w;j++)g[i][j] = 0;
    }

    cin >> sx >> sy >> gx >> gy >> n;
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;
      if(d==0){
	for(int j=0;j<2;j++){
	  for(int k=0;k<4;k++){
	    g[y+j][x+k] = c;
	  }
	}
      }else{
	for(int j=0;j<4;j++){
	  for(int k=0;k<2;k++){
	    g[y+j][x+k] = c;
	  }
	}
      }
    }
    /*
    for(int i=1;i<=h;i++){
      for(int j=1;j<=w;j++){
	cout << g[i][j] << " ";
      }
      cout << endl;
    }
    */

    if(!g[sy][sx] || !g[gy][gx] || g[sy][sx] != g[gy][gx]){
      cout << "NG\n";
    }else{
      rec(sy,sx,g[sy][sx]);
      cout << (use[gy][gx]?"OK":"NG") << endl;
    }
  }
}

C++: #include <iostream>
#include <cstring>
#include <queue>
using namespace std;
int main(){
	while (1) {
		int w,h,xs,ys,xg,yg,n;
		cin>>w>>h;
		if(!w) break;
		cin>>xs>>ys>>xg>>yg>>n;
		int board[w][h];
		bool visited[w][h];
		memset(board,0,sizeof board);
		memset(visited,0,sizeof visited);
		queue<pair<int,int>> que;
		que.emplace(--xs,--ys);
		visited[xs][ys] = true;
		xg--;yg--;
		int area[2][2][8] = {{{-1,0,1,2,-1,0,1,2},{-1,-1,-1,-1,0,0,0,0}},
		    {{-1,-1,-1,-1,0,0,0,0},{-1,0,1,2,-1,0,1,2}}};
		for (int i = 0; i < n; i++) {
			int c,d,x,y;
			cin>>c>>d>>x>>y;
			for (int i = 0; i < 8; i++)
				board[area[d][0][i]+x][area[d][1][i]+y] = c;
		}
		constexpr int dx[]={0,-1,1,0},dy[]={1,0,0,-1};
		while (!que.empty()) {
			auto now = que.front(); que.pop();
			for (int i = 0; i < 4; i++) {
				int nx = now.first+dx[i],ny = now.second+dy[i];
				if(nx >= 0 && nx < w && ny >= 0 && ny < h && board[nx][ny] == board[xs][ys] && !visited[nx][ny]){
					visited[nx][ny] = true;
					que.emplace(nx,ny);
				}
			}
		}
		puts((visited[xg][yg]) ? "OK" : "NG");
	}
	return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

int W,H, f[100][100];
bool memo[100][100];
int dx[]={-1,0,1,0};
int dy[]={0,-1,0,1};

void dfs(int x, int y, int c)
{
	memo[x][y]=1;
	
	for(int i=0; i<4; i++)
	{
		int tx=x+dx[i], ty=y+dy[i];
		if(tx<0||ty<0||tx>=W||ty>=H) continue;
		if(f[tx][ty]!=c) continue;
		if(memo[tx][ty]) continue;
		dfs(tx,ty,c);
	}
}

int main()
{
	while(scanf("%d%d", &W,&H), (W||H))
	{
		int xs,ys,xg,yg,N;
		scanf("%d%d%d%d%d", &xs,&ys,&xg,&yg,&N);
		xs--;ys--;xg--;yg--;
		while(N--)
		{
			int c,d,x,y;
			scanf("%d%d%d%d", &c,&d,&x,&y);
			x--; y--;
			
			int w=2, h=4;
			if(d==0) swap(w,h);
			for(int i=y; i<y+h; i++)
			for(int j=x; j<x+w; j++)
				f[j][i]=c;
		}
		
		memset(memo,0,sizeof(memo));
		dfs(xs,ys,f[xs][ys]);
		
		puts(memo[xg][yg]?"OK":"NG");
	}
}

C++: #include<iostream>
#include<algorithm>
#include<string>
#include<queue>
	using namespace std;
	
	int xs,ys,w,h,n,ban[111][111],xg,yg;bool visited[101][101];
		int vecx[4]={1,0,-1,0},vecy[4]={0,1,0,-1};
	struct P{
		int xx,yy;
	};	
	
	queue<P> jo;
	bool bfs(void){	
		while(!jo.size()==0){
		P now=jo.front();jo.pop();
		if(now.xx==-1||now.yy==-1)return false;
		if(now.xx==xg&&now.yy==yg)return true;
		int x=now.xx,y=now.yy;
		for(int i=0;i<4;i++){
			if(ban[x+vecx[i]][y+vecy[i]]==ban[xs][ys]){
				if(!visited[x+vecx[i]][y+vecy[i]]){
				P next={x+vecx[i],y+vecy[i]};
				visited[x+vecx[i]][y+vecy[i]]=true;
				jo.push(next);
				}
			}
		}
	}
		return 0;
	}

int main(){

	while(cin>>w>>h&&w&&h){
	cin>>xs>>ys>>xg>>yg>>n;
		P start={xs,ys};
	jo.push(start);
	for(int i=0;i<101;i++)
	for(int j=0;j<101;j++)ban[i][j]=-1,visited[i][j]=false;
	
	for(int i=0;i<n;i++){
		int c,d,x,y;
		cin>>c>>d>>x>>y;
		if(!d){
			for(int i=x;i<x+4;i++){
				for(int j=y;j<y+2;j++){
					ban[i][j]=c;
				}
			}
		}
		else{
		for(int i=x;i<x+2;i++){
				for(int j=y;j<y+4;j++){
					ban[i][j]=c;
				}
			}
		}
		}
		if(bfs())cout<<"OK"<<endl;
	else cout<<"NG"<<endl;
	}
	return 0;
	}