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 <algorithm>
#include <string>
#include <vector>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <unordered_map>
#include <ctime>
#include <list>
#include <numeric>
#include <utility>
#include <ctime>
#define INF 100000000
#define LINF 9000000000000000000
#define mod 1000000007
 
#define rep(i,n) for(int i=0;i<int(n);i++)
#define REP(i,a,b) for(int i=(a);i<int(b);i++)
#define all(x) (x).begin(),x.end()
#define pb push_back
#define mp make_pair
#define MOD(x) (x%(mod))
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef pair<int,int> pi;
 
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
bool debug=false;

/*---------------------------------------------------*/

int maze[305][305];
int w,h,xs,ys,xg,yg;

void init(){
  rep(i,305){
    rep(j,305){
      maze[i][j]=-1;
    }
  }
}

bool bfs(int c){
  queue<int>que;
  que.push(xs);
  que.push(ys);
  while(que.size()){
    int x=que.front();que.pop();
    int y=que.front();que.pop();
    if(x==xg&&y==yg)return true;
    for(int i=0;i<4;i++){
      if(0<=x+dx[i]&&x+dx[i]<=w&&0<=y+dy[i]&&y+dy[i]<=h&&maze[y+dy[i]][x+dx[i]]==c){
	que.push(x+dx[i]);
	que.push(y+dy[i]);
	maze[y+dy[i]][x+dx[i]]=-1;
      }
    }
  }
  return false;
}

int main(){
  int n,c,d,x,y;
  while(cin>>w>>h){
    if(w==0&&h==0)break;
    init();
    cin>>xs>>ys;
    cin>>xg>>yg;
    cin>>n;
    rep(i,n){
      cin>>c>>d>>x>>y;
      if(d==0){
	rep(j,2){
	  rep(k,4){
	    maze[y+j][x+k]=c;
	  }
	}
      }else if(d==1){
	rep(j,4){
	  rep(k,2){
	    maze[y+j][x+k]=c;
	  }
	}
      }
    }
    if(bfs(c))cout<<"OK"<<endl;
    else cout<<"NG"<<endl;
  }
  return 0;
}

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

int f[102][102];

void draw(int c,int d,int x,int y){
    if(d){
        for(int i=x;i<x+2;i++){
            for(int j=y;j<y+4;y++){
                f[i][j]=c;
            }
        }
    }else{
        for(int i=x;i<x+4;i++){
               for(int j=y;j<y+2;y++){
                    f[i][j]=c;
                }
        }
    }
}

bool judge(int c,int x,int y){
    if(c==f[x][y]){
        return true;
    }
    return false;
}

bool DFS(int xs,int ys,int xg,int yg){
    if(xs!=xg||ys!=yg){
        if(judge(f[xs][ys],xs+1,ys)){
            if(DFS(xs+1,ys,xg,yg)){
                return true;
            }
        }
          
        if(judge(f[xs][ys],xs-1,ys)){
            if(DFS(xs-1,ys,xg,yg)){
                return true;
            }
        }
        if(judge(f[xs][ys],xs,ys+1)){
            if(DFS(xs,ys+1,xg,yg)){
                return true;
            }
        }
        if(judge(f[xs][ys],xs,ys-1)){
            if(DFS(xs,ys,xg,yg-1)){
                return true;
            }
        }
        if(!(judge(f[xs][ys],xs+1,ys)||judge(f[xs][ys],xs-1,ys)||judge(f[xs][ys],xs,ys+1)||judge(f[xs][ys],xs,ys-1))){
            return false;
        }
    }
    return true;
}

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

        for(int i=0;i<n;i++){
            cin>>c>>d>>x>>y;
            draw(c,d,x,y);
        }
        if(DFS(xs,ys,xg,yg)){
            cout<<"OK"<<endl;
        }else{
            cout<<"NG"<<endl;
        }
    }
    return 0;
}

C++: #include<iostream>

int field[102][102];//y,x
bool flag;
int sx,sy,gx,gy,col;

void erase(){
	for(int i=0; i<102; i++)
		for(int j=0; j<102; j++)
			field[i][j] = 0;
}

void DFS(int x, int y){
	if(field[y][x] != col)
		return;
	if(x == gx && y == gy){
		flag = true;
		return;
	}
	if(sx < gx)
	DFS(x+1, y);
	if(flag)
		return;
	if(sy < gy)
	DFS(x, y+1);
	if(flag)
		return;
	if(sx > gx)
	DFS(x-1, y);
	if(flag)
		return;
	if(sy > gy)
	DFS(x, y-1);
}

int main(){
	int n,c,d,bx,by;
	while(true){
		flag = false;
		erase();

		std::cin >> c >> d;
		if(!c && !d)
			return 0;

		std::cin >> sx >> sy;
		std::cin >> gx >> gy;

		std::cin >> n;
		for(int i=0; i<n; i++){
			std::cin >> c >> d >> bx >> by;
			if(d==0)
				for(int h=by; h<by+2; h++)
					for(int w=bx; w<bx+4; w++)
						field[h][w] = c;
			else
				for(int h=by; h<by+4; h++)
					for(int w=bx; w<bx+2; w++)
						field[h][w] = c;
		}

		col = field[gy][gx];
		DFS(sx, sy);
		if(flag)
			std::cout << "OK\n";
		else
			std::cout << "NG\n";
	}
}