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 <cmath>
#include <ctime>
#include <algorithm>
#include <iostream>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <list>
#include <deque>
#include <stack>
#include <bitset>
#include <functional>
#include <numeric>
#include <utility>
#include <iomanip>
#include <cstdio>
#include <cctype>
#include <queue>
#include <complex>
#include <climits>

typedef long long ll;

using namespace std;

int maze[110][110];
int f[110][110];
int w, h, xs, ys, xg, yg, res = 0;
int color;

void dfs(int cx, int cy){
	if(f[cx][cy]) return ;
	f[cx][cy] = 1;
	if(cx == xg && cy == yg){
		res = 1;
		return ;
	}
	for(int dx=-1; dx<=1; ++dx){
		for(int dy=-1; dy<=1; ++dy){
			if(abs(dx-dy) != 1) continue;
			int nx = cx + dx, ny = cy + dy;
			if(maze[nx][ny] == color){
				dfs(nx, ny);
			}
		}
	}
	return ;
}


int main(void){
	int n;
	while(cin >> w >> h){
		if(w == 0 && h == 0) break;
		cin >> xs >> ys >> xg >> yg >> n;
		for(int i=0; i<110; ++i){
			for(int j=0; j<110; ++j){
				maze[i][j] = 0;
				f[i][j] = 0;
			}
		}

		for(int i=0; i<n; ++i){
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			if(d == 0){
				for(int j=y; j<=y+1; ++j){
					for(int k=x; k<=x+3; ++k){
						maze[j][k] = c;
					}
				}
			}
			if(d == 1){
				for(int j=y; j<=y+3; ++j){
					for(int k=x; k<=x+1; ++k){
						maze[j][k] = c;
					}
				}
			}
		}

		color = maze[xs][ys];
		if(color == 0){
			cout << "NG" << endl;
			continue;
		}

		dfs(xs, ys);

		if(res){
			cout << "OK" << endl;
		} else {
			cout << "NG" << endl;
		}
	}

	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define int				long long
#define FOR( i, m, n )  for( int (i) = (m); (i) < (n); (i)++ )
#define REP( i, n )     FOR( i, 0, n )
#define REPR( i, m )	for( int (i) = (m); (i) >= 0; (i)-- )
#define REPONE( i, n )	FOR( i, 1, n + 1 )
#define ALL( a )        (a).begin(), (a).end()
#define MP				make_pair
#define X				first.first
#define Y				first.second

typedef pair<int, int> P;

template<class T>bool chmax( T& a, const T& b ) { if( a < b ) { a = b; return 1; } return 0; }
template<class T>bool chmin( T& a, const T& b ) { if( a > b ) { a = b; return 1; } return 0; }

const int INF = 1e9;
const int MOD = 1e9 + 7;

int dx[4] = { 1, -1, 0, 0 };
int dy[4] = { 0, 0, 1, -1 };

int maze[150][150];
int W, H;
bool flag;

void dfs( int sx, int sy, int gx, int gy, int color ) {
	REP( i, 4 ) {
		int nx = sx + dx[i];
		int ny = sy + dy[i];

		if( nx >= 0 && nx < W && ny >= 0 && ny < H && maze[nx][ny] == color ) {
			if( nx == gx && ny == gy ) flag = true;
			maze[nx][ny] = -1;
			dfs( nx, ny, gx, gy, color );
		}
	}
}

signed main() {
	while( cin >> W >> H, W ) {
		fill( maze[0], maze[150], -1 );

		int sx, sy, gx, gy, n;
		cin >> sx >> sy >> gx >> gy >> n;

		REP( i, n ) {
			int color, d, x, y;
			cin >> color >> d >> x >> y;

			if( d == 0 ) {
				REP( i, 4 ) {
					maze[x + i][y] = color;
					maze[x + i][y + 1] = color;
				}
			} else {
				REP( i, 4 ) {
					maze[x][y + i] = color;
					maze[x + 1][y + i] = color;
				}
			}
		}

		if( maze[sx][sy] == -1 ) cout << "NG" << endl;
		else {
			flag = false;
			dfs( sx, sy, gx, gy, maze[sx][sy] );
			cout << ( flag ? "OK" : "NG" ) << endl;
		}
	}
}

C++: #include <bits/stdc++.h>
using namespace std;


bool b;

void dfs(int board[][102] ,int x , int y , int w , int h , int xg , int yg , int sc){
	if(x==xg&&y==yg) {b=true;return;}
	for(int i=0;i<4;++i){
		int dx[]={1,0,-1,0};
		int dy[]={0,1,0,-1};
		int tx=x+dx[i];
		int ty=y+dy[i];
		if(tx<=0||ty<=0||tx>w||ty>h) continue;
		if(board[tx][ty]!=sc || board[tx][ty]==0) continue;
		if(b) continue;
		dfs( board , tx,ty,w,h,xg,yg,sc);
	}
}

int main(){
	int w , h;
	while(cin >> w >> h , w||h){
		int xs , ys , xg , yg ;
		int n;
		b=false;
		int board[102][102]={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){
				for(int k=0;k<2;++k){
					for(int j=0;j<4;++j){
						board[x+j][y+k]=c;
					}
				}
			} else {
				for(int k=0;k<4;++k){
					for(int j=0;j<2;++j){
						board[x+j][y+k]=c;
					}
				}
			}
		}
		
		int sc=board[xs][ys];
		int gc=board[xg][yg];
		if(sc!=gc) {}
		else dfs(board ,xs,ys , w , h , xg , yg , sc);
		cout << ( b ? "OK" : "NG") << endl;
	}
	return 0;
}

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;
    cin >> xs >> ys >> xg >> yg >> n;



  DFS(xs,ys,F[xs][ys]);
  if(xs == 8){
    cout << "OK" << endl;
  } else {
    cout << "NG" << endl;
  }
  }
}