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;

int F[102][102];


int DFS(int Y,int X,int c){
  int cnt = 0;
  if(F[Y][X] != c){
    return 0;
  }

  F[Y][X] = -1;
  cnt += DFS(Y-1,X  ,c);
  cnt += DFS(Y  ,X+1,c);
  cnt += DFS(Y+1,X  ,c);
  cnt += DFS(Y  ,X-1,c);
  return cnt;
}


int main(){
  int w,h,xs,ys,xg,yg,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;

      for(int i=0;i<102;i++){
        for(int j=0;j<102;j++){
                F[i][j]=0;
        }
      }
    cin >> xs >> ys >> xg >> yg >> 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++){
          F[x+j][y] = c;
          F[x+j][y+1] = c;
        }
      } else {
        for(int j=0;j<4;j++){
          F[x][y+j] = c;
          F[x+1][y+j] = c;
        }
      }
    }
  DFS(xs,ys,F[xs][ys]);
  if(x == 8){
    cout << "OK" << endl;
  } else {
    cout << "NG" << endl;
  }
  }
}

C++: #include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
bool N[102][102];
int map[102][102],R,ga,gb,w,h;
bool block(int ,int);
int main()
{
	int i,a,n,b,c,d,X=0,Y=0,x,y;
	cin>>w>>h;
	while(w!=0||h!=0){
		memset(map,0,sizeof(map));
		memset(N,false,sizeof(N));
		cin>>X>>Y;
		cin>>ga>>gb;
		cin>>n;
		for(i=0;i<n;i++){
			cin>>c>>d>>x>>y;
			if(d){
				map[y][x]=c;
				map[y+1][x]=c;
				map[y+2][x]=c;
				map[y+3][x]=c;
				map[y][x+1]=c;
				map[y+1][x+1]=c;
				map[y+2][x+1]=c;
				map[y+3][x+1]=c;

			}
			else{
				map[y][x]=c;
				map[y+1][x+1]=c;
				map[y+1][x+2]=c;
				map[y+1][x+3]=c;
				map[y+1][x]=c;
				map[y][x+1]=c;
				map[y][x+2]=c;
				map[y][x+3]=c;

			}
		}
		R=map[Y][X];
		if(R==map[gb][ga]&&R!=0){
			if(block(Y,X)) cout<<"OK"<<endl;
		        else cout<<"NG"<<endl;
		}
		else cout<<"NG"<<endl;
		//for(i=0;i<h;i++){
			//for(j=0;j<w;j++){
			//	cout<<map[i][j];
			//}
				
	//		cout<<endl;
		//}
		cin>>w>>h;
	}
	return 0;
}
bool block(int b,int a)
{
	//if(f==1) return 1;
	N[b][a]=true;
	if(ga==a&&gb==b) return true;
	if(a+1!=w){
		if(map[b][a+1]==R&&N[b][a+1]==false) return block(b,a+1);} //???
	if(b+1!=h){
		if(map[b+1][a]==R&&N[b+1][a]==false) return block(b+1,a);} //???
	if(a-1!=-1){
		if(map[b][a-1]==R&&N[b][a-1]==false) return block(b,a-1);} //???
	if(b-1!=-1){
		if(map[b-1][a]==R&&N[b-1][a]==false) return block(b-1,a);} //???
	return false;
}

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

using namespace std;

int w,h;
int map[101][101];
int xg,yg;

int dx[]={1,-1,0,0};
int dy[]={0,0,1,-1};
void mapout()
{
  for(int xx=0;xx<h;xx++,cout<<endl)
    for(int yy=0;yy<w;yy++)
      if(map[xx][yy]!=-1)
      cout<<map[xx][yy];
      else
	cout<<"X";
}

bool check(int x,int y)
{
  //  cout<<"check "<<x<<" "<<y<<";"<<map[x][y]<<endl;
  if(x==xg&&y==yg)
    return true;
  int buf=map[x][y];
  map[x][y]=-1;
  for(int i=0;i<4;i++)
    {
      if(x+dx[i]>=0&&x+dx[i]<h&&
	 y+dy[i]>=0&&y+dy[i]<w&&
	 buf==map[x+dx[i]][y+dy[i]] &&
	 map[x+dx[i]][y+dy[i]]!=-1 &&
	 check(x+dx[i],y+dy[i]))
	return true;
    }

  
  return false;
}

int main()
{
  for(;cin>>w>>h,w;)
    {
      memset(map,-1,sizeof(map));
      int xs,ys;
      cin>>xs>>ys;
      cin>>xg>>yg;
      xs--;ys--;
      xg--;yg--;
      
      int n;
      cin>>n;
      for(;n--;)
	{
	  int c,d,x,y;
	  cin>>c>>d>>y>>x;
	  x--;y--;
	  if(d==0)
	    {
	      for(int xx=x;xx<x+2;xx++)
		for(int yy=y;yy<y+4;yy++)
		  map[xx][yy]=c;
	    }
	  else
	    {
	      for(int xx=x;xx<x+4;xx++)
		for(int yy=y;yy<y+2;yy++)
		  map[xx][yy]=c;
	    }
	}
      ///   mapout();
      if(check(xs,ys))
	cout<<"OK"<<endl;
      else 
	cout<<"NG"<<endl;
    }
  
  

}

C++: #include<iostream>
#include<cstring>
using namespace std;
int map[110][110];
int com[110][110];
int lx,ly,sx,sy,gx,gy;
int py[4]={1,0,-1,0};
int px[4]={0,1,0,-1};
int fl;
int mei(int zx,int zy ,int cei[][110])
{
	int i;
	if(zx==gx && zy==gy)
	{
		fl=1;
		return 0;
	}
	cei[zy][zx]=1;
	for(i=0;i<4;i++)
	{
		if(cei[zy+py[i]][zx+px[i]]==0 && map[sy][sx]==map[zy+py[i]][zx+px[i]])
		{
			mei(zx+px[i],zy+py[i],cei);
			if(fl) return 0;
		}
	}
	cei[zy][zx]=0;
	return 0;
}
int main()
{
	int n,col,muk,vx,vy;
	int i,j,t;
	while(cin >> lx >> ly, lx!=0 && ly!=0)
	{
		fl=0;
		cin >> sx >> sy >> gx >> gy >> n;
		memset(map,0,sizeof(map));
		memset(com,0,sizeof(com));
		for(i=0;i<n;i++)
		{
			cin >> col >> muk >> vx >> vy;
			if(muk==0)
			{
				for(j=vy;j<2+vy;j++)
				{
					for(t=vx;t<4+vx;t++)
					{
						map[j][t]=col;
					}
				}
			}
			else
			{
				for(j=vy;j<4+vy;j++)
				{
					for(t=vx;t<2+vx;t++)
					{
						map[j][t]=col;
					}
				}
			}
		}
		if(map[sy][sx]!=map[gy][gx])
		{
			cout << "NG" << endl;
			continue;
		}
		mei(sx,sy,com);
		if(fl) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
	return 0;
}

C++: #include<iostream>

using namespace std;

int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int N;
int W,H;
pair<int,int>s;
pair<int,int>g;
int sc;
int map[103][103]={0};
bool flag[103][103]={0};
int ans=0;

bool se(int x,int y){
	if(x==g.first && y==g.second)ans=1;
	for(int i=0;i<4;i++){
		int xx=x+dx[i];
		int yy=dy[i]+y;
		if(xx>=0 &&yy>=0 &&xx<W &&yy<H && sc==map[xx][yy]&& flag[xx][yy]==0){
			flag[xx][yy]=1;
			se(xx,yy);
		}
	}
	return 0;
}


int main(){
	
	while(cin>>W>>H>>s.first>>s.second>>g.first>>g.second>>N,H,W){
		int d,c,x,y;
		
		for(int i=0;i<N;i++){
			cin>>c>>d>>x>>y;
			if(d){
				for(int i=x;i<x+2;i++){
					for(int j=y;j<y+4;j++){
						map[i][j]=c;
				}
			}
		}else{
			for(int i=x;i<x+4;i++){
				for(int j=y;j<y+2;j++){
					map[i][j]=c;
				}
			}
		}
		}
		sc=map[s.first][s.second];
		flag[s.first][s.second]=1;
		
		se(s.first,s.second);
		if(ans)cout<<"OK"<<endl;
		else cout<<"NG"<<endl;
		ans=0;
		int map[103][103]={0};
		bool flag[103][103]={0};
		/*
		if(se(s.first,s.second))cout<<"OK"<<endl;
		else cout<<"NG"<<endl;
		*/
	}
	return 0;
}