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<cstdio>
#include<iostream>

using namespace std ;

int mx[] = { 1 ,0 ,0 ,-1 } ;
int my[] = { 0 ,1 ,-1 ,0 } ;

int w ,h ;
int gx ,gy ;

int ok_or_ng( int x ,int y ,bool came[][ 110 ] )
{
	/*came[ y ][ x ] = false ;*/

	if( x == gx && y == gy )
		return 1 ;

	for( int i = 0 ; i < 4 ; i++ )
	{
		int xx = x + mx[ i ] ;
		int yy = y + my[ i ] ;
		if( xx > 0 && xx <= w && yy > 0 && yy <= h && came[ yy ][ xx ] )
		{
			came[ yy ][ xx ] = false ;
			return ok_or_ng( xx ,yy ,came ) ;
		}
	}
	return 0 ;
}

void wide( int x ,int y ,int c ,int map[][ 110 ] )
{

	for( int i = 0 ; i < 2 ; i++ )
	{
		for( int j = 0 ; j < 4 ; j++ )
			map[ y + i ][ x + j ] = c ;
	}

	return ;
}

void high( int x ,int y ,int c ,int map[][ 110 ] )
{

	for( int i = 0 ; i < 4 ; i++ )
	{
		for( int j = 0 ; j < 2 ; j++ )
			map[ y + i ][ x + j ] = c ;
	}

	return ;
}

int main()
{
	while( cin >> w >> h )
	{
		if( w == h && w == 0 )
		return 0 ;
		bool came[ 110 ][ 110 ] = { false } ;
		int map[ 110 ][ 110 ] = { 0 } ;

		int sx ,sy ;

		cin >> sx >> sy ;
		cin >> gx >> gy ;

		int n ;
		cin >> n ;					// 0 w	1 h

		int c ,d ,x, y ;
		for( int i = 0 ; i < n ; i++ )
		{
			cin >> c >> d >> x >> y ;
			d ? high( x ,y ,c ,map ) : wide( x ,y ,c ,map ) ;
		}

		c = map[ gy ][ gx ] ;

		came[ gy ][ gx ] = false ;	//

		for( int i = 1 ; i <= h ; i++ )
		{
			for( int j = 1 ; j <= w ; j++ )
			{
				if( map[ i ][ j ] == c )
					came[ i ][ j ] = true ;
			}
		}

		ok_or_ng( sx ,sy ,came ) ? printf( "OK\n" ) : printf( "NG\n" ) ;
	}
}

C++: #include<bits/stdc++.h>
using namespace std;
#define ANSWER(x) cout<<x<<endl
#define debug(x) cout<<#x<<": "<<x
const int BA = 1000;
const int INFTY = (1<<21);
int xg,yg,w,h,gc;
int maps[101][101];
int solve(int ys,int xs);
int main(){
  int tate[2] = {2,4};
  int yoko[2] = {4,2};
  int xs,ys,n;
  int c[101],d[101],x[101],y[101];
  while(1){
    fill(maps[0],maps[101],0);
    cin >> w >> h;
    if(w==0 && h==0)break;
    cin >> xs >> ys >> xg >> yg >> n;
    xs--;ys--;xg--;yg--;
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
      x[i]--;y[i]--;
    }
    for(int i=0;i<n;i++){
      for(int j=y[i];j<y[i]+tate[d[i]];j++){
	for(int k=x[i];k<x[i]+yoko[d[i]];k++){
	  if(j == ys && k == xs)gc = c[i];
	  maps[j][k] = c[i];
	}
      }
    }
    /* for(int i=0;i<h;i++){
       for(int j=0;j<w;j++){
       cout << maps[i][j];
       }
       cout << endl;
       }*///マップ確認用
    if(solve(ys,xs))cout << "OK\n";
    else cout << "NG\n";
  }
}
int solve(int ys,int xs){
  if(xs < 0 || ys < 0 || xs > w-1 || ys > h-1 || maps[ys][xs] == 0 || maps[ys][xs] != gc){
    return 0;
  }
  else if(maps[ys][xs] == maps[yg][xg]){
    return 1;
  }
  maps[ys][xs] = 0;
  return solve(ys+1,xs) + solve(ys,xs+1)+ solve(ys-1,xs) + solve(ys,xs-1);
}

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

char F[101][101];

void Block(int c, int d, int x, int y){
	if(d==0){
    	for(int i=0;i<4;i++){
    		F[y][x+i]=c;
			F[y+1][x+i]=c;
    	}
  	}else{
    	for(int i=0;i<4;i++){
    		F[y+i][x]=c;
    		F[y+i][x+1]=c;
    	}
	}
}
void DFS(int y,int x,int c){
	if(F[y][x]!=c)
		return;

	F[y][x] = 6;

    DFS(y-1,x  ,c);
    DFS(y  ,x+1,c);
    DFS(y+1,x  ,c);
    DFS(y  ,x-1,c);
}
int main(){
	while(true){
		int w,h;
		cin>>w>>h;
		if(w==0&&h==0){break;}
		int xs,ys;
		cin>>xs>>ys;
		int xg,yg;
		cin>>xg>>yg;
		int n;
		cin>>n;
		int c,d,x,y;
		for(int i=0;i<n;i++){
			cin>>c>>d>>x>>y;
			Block(c,d,x,y);
		}
		DFS(ys,xs,F[ys][xs]);
		if(F[yg][xg]==6){
			cout<<"OK"<<endl;
		}else{
			cout<<"NG"<<endl;
		}
	}
    return 0;
}

C++: #include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define RFOR(i,a,b) for(int i=(b) - 1;i>=(a);i--)
#define REP(i,n) for(int i=0;i<(n);i++)
#define RREP(i,n) for(int i=n-1;i>=0;i--)

#define PB push_back
#define INF INT_MAX/3
#define ALL(a) (a).begin(),(a).end()
#define CLR(a) memset(a,0,sizeof(a))

typedef long long int ll;

using namespace std;

bool u[101][101];
int board[101][101];
int gc;
int h,w,n;
int xs,ys,xg,yg;
int dx[] = {-1,0,0,1};
int dy[] = {0,1,-1,0};
bool saiki(int x,int y){
    bool ret = false;
    if(x==xg&&y==yg) return true;
    REP(i,4){
	int nx = x + dx[i];
	int ny = y + dy[i];
	if(1<=nx&&nx<=w&&1<=ny&&ny<=h&&board[ny][nx] == gc&&!u[ny][nx]){
	    u[ny][nx] = true;
	    ret = ret || saiki(nx,ny);
	}
    }
    return ret;
}

int main(){
    while(true){
	memset(board,0,sizeof(board));
	memset(u,false,sizeof(u));
	cin >> w >> h;
	if(w == 0 && h == 0) break;
	cin >> xs >> ys >> xg >> yg;
	cin >> n;
	REP(i,n){
	    int c,d,x,y;
	    cin >> c >> d >> x >> y;
	    if(d == 1){
		REP(i,2){
		    REP(j,4){
			board[y+j][x+i] = c;
		    }
		}
	    }else{
		REP(i,4){
		    REP(j,2){
			board[y+j][x+i] = c;
		    }
		}
	    }
	}
	gc = board[ys][xs];
	if(gc != board[yg][xg]) cout << "NG" << endl;
	else{
	    if(saiki(xs,ys)){
		cout << "OK" << endl;
	    }else cout << "NG" << endl;
	}


    }
    return 0;
}