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<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;
		}
	}
	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 F[102][102];

void DFS(int Y, int X, int c) {
	//cout << Y << " " << X << endl;
	if (F[Y][X] != c || c != 0)
		return;
	F[Y][X] = 10;
	DFS(Y - 1, X, c);//???
					 //DFS(Y - 1, X+1, A_ito);//??????
	DFS(Y, X + 1, c);//???
					 //DFS(Y + 1, X+1, A_ito);//??????
	DFS(Y + 1, X, c);//???
					 //DFS(Y + 1, X-1, A_ito);//??????
	DFS(Y, X - 1, c);//???
					 //DFS(Y - 1, X-1, A_ito);//??????
}


int main()
{
	int xs, ys, xg, yg, n;
	int c, d, x, y;
	int W = 1, H = 1;

	while ((W != 0) && (H != 0)) {
		cin >> W >> H;
		cin >> xs >> ys >> xg >> yg >> n;
		for (int i = 1;i <= n;i++) {
			cin >> c >> d >> x >> y;
			if (d == 0) {
				F[x][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y] = c;
				F[x + 1][y + 1] = c;
				F[x + 2][y] = c;
				F[x + 2][y + 1] = c;
				F[x + 3][y] = c;
				F[x + 3][y + 1] = c;
			}
			if (d == 1) {
				F[x][y] = c;
				F[x + 1][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y + 1] = c;
				F[x][y + 2] = c;
				F[x + 1][y + 2] = c;
				F[x][y + 3] = c;
				F[x + 1][y + 3] = c;
			}
		}
		if (F[ys][xs] != 0)
			DFS(ys, xs, F[ys][xs]);

		if (F[yg][xg] == 10) {
			cout << "OK" << endl;
		}
		else { cout << "NG" << endl; }
		/*for (int i = 0;i < H;i++) {
			for (int j = 0;j < W;j++) {
				F[i][j] = 0;
			}
		}
		*/
	}

	return 0;
}

C++: #include<iostream>
#include<queue>
#define MAX 100
using namespace std;

int map[MAX+2][MAX+2];
bool check[MAX+2][MAX+2];
int dx[4] = { -1,1,0,0};
int dy[4] = { 0,0,-1,1};

int main () {

  while ( true ) {

    queue<int> next;

    while( !next.empty() ) {
      next.pop();
    }
    
    int w,h;
    cin >> w >> h ;

    if ( w == 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<h+2; i++ ) {
      for ( int j=0; j<w+2; j++ ) {
	map[i][j] = 0;
	check[i][j] = true;
      }
    }

    for ( int i=0; i<n; i++ ) {
      cin >> c >> d >> x >> y;
      
      //int count = 0;
      for ( int j=0; j<2; j++ ) {
	for ( int k=0; k<4; k++ ) {
	  //cout << count;
	  if ( d == 0 ) {
	    map[y+j][x+k] = c;
	  } else {
	    map[y+k][x+j] = c;
	  }
	}
      }
      //cout << endl;
    }
    next.push(y*1000 + x );

    int point;
    bool goal = false;

    int sc = map[ys][xs];

    for ( int i=0; i<=h; i++ ) {
      for ( int j=0; j<=w; j++ ) {
	cout << map[i+1][j+1];
      }
      cout << endl;
    }
    cout << endl;

    if ( map[yg][xg] == sc ) {
	
      while ( !next.empty() ) {
	point = next.front();
	next.pop();

	check[point/1000][point%1000] = false;
	if (map[point/1000][point%1000] == 0 )
	  continue;

	if (point == yg*1000+xg) {
	  if ( sc == map[yg][xg] )
	    goal = true;
	  break;
	}
	for ( int i=0; i<4; i++ ) {
	  if ( check[point/1000+dy[i]][point%1000+dx[i]] ) {
	    check[point/1000+dy[i]][point%1000+dx[i]] = false;
	    if ( map[point/1000+dy[i]][point%1000+dx[i]] == sc ) {
	      next.push((point/1000+dy[i])*1000+point%1000+dx[i]);
	    }
	  }
	}
      }
    }

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


  }


}

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

int w, h;
int xs, ys, xg, yg;
int cs;

int calc(std::vector<std::vector<int> >&v, int x, int y){

	int res = 0;

	v[x][y] = 0;

	if (y == xg&&x == yg)return 1;

	if (x < h - 2 && v[x + 1][y] == cs)res += calc(v, x + 1, y);
	if (x > 0 && v[x - 1][y] == cs)res += calc(v, x - 1, y);
	if (y < w - 2 && v[x][y + 1] == cs)res += calc(v, x, y + 1);
	if (y > 0 && v[x][y - 1] == cs)res += calc(v, x, y - 1);

	return res;
}

int main(){

	while (std::cin >> w >> h){

		if (w == 0 && h == 0)break;

		std::cin >> xs >> ys >> xg >> yg;

		xs--, ys--, xg--, yg--;

		int n;
		std::cin >> n;

		std::vector<std::vector<int> >v(h, std::vector<int>(w, 0));

		for (int i = 0; i < n; i++){
			int c, d, x, y;
			std::cin >> c >> d >> x >> y;

			x--, y--;

			if (d == 0){
				for (int j = y; j < y + 2; j++){
					for (int k = x; k < x + 4; k++){
						v[j][k] = c;
					}
				}
			}
			if (d == 1){
				for (int j = y; j < y + 4; j++){
					for (int k = x; k < x + 2; k++){
						v[j][k] = c;
					}
				}
			}
		}

		cs = v[ys][xs];

		if (cs == v[yg][xg] && cs != 0){
			if (calc(v, ys, xs))std::cout << "OK" << std::endl;
			else std::cout << "NG" << std::endl;
		}
		else std::cout << "NG" << std::endl;
	}
	return 0;
}