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 Array[200][200];
bool is_goal = false;
#define START 20
#define GOAL 30

void DFS(int h,int w,int c){

  if(!is_goal){

    if(Array[h][w] == GOAL){
      is_goal = true;
      return;
    }

    if(Array[h][w] != c || Array[h][w] == 0){
      return;
    }

    int tmp=Array[h][w];

    Array[h][w] = 0;

    DFS(h-1,w,tmp);
    DFS(h,w+1,tmp);
    DFS(h+1,w,tmp);
    DFS(h,w-1,tmp);
  }

}

int main(){

    while(1){
      int H,W;
      int Start[2],Goal[2];
      int BlockNum;
      int color,dir,xpos,ypos;

      is_goal = false;

      for(int i=0;i<200;i++){
        for(int j=0;j<200;j++){
          Array[i][j] = 0;
        }
      }

      cin >> H >> W;

      if(H == 0 && W == 0){
        break;
      }

      cin >> Start[0] >> Start[1];


      cin >> Goal[0] >> Goal[1];


      cin >> BlockNum;

      for(int i=0;i<BlockNum;i++){
        cin >> color >> dir >> xpos >> ypos;
        for(int i=0;i<4;i++){
          for(int j=0;j<2;j++){
            if(!dir){//?¨?
              Array[xpos+i][ypos+j] = color;
            }
            else{
              Array[xpos+j][ypos+i] = color;
            }
            //cout << i << " " << j << endl;
          }
        }
      }
      Array[Goal[0]][Goal[1]] = GOAL;
      /*for(int i=1;i<=H;i++){
        for(int j=1;j<=W;j++){
          cout << Array[i][j];
        }
        cout << endl;
      }*/

      DFS(Start[0],Start[1],Array[Start[0]][Start[1]]);

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

  }
    return 0;
}

C++: #include<iostream>
using namespace std;
int w, h, xs, ys, xg, yg, stage[101][101] = {};
int ny[4] = { 0, 1, 0, -1 }, nx[4] = { 1, 0, -1, 0 };
int bc;
bool ans = false;
void func(int x, int y){
	if (x == xg && y == yg){
		ans = true;
	}
	for (int i = 0; i < 4; i++){
		if (stage[y + ny[i]][x + nx[i]] != bc) return;
		func(x + nx[i], y + ny[i]);
	}
}
int main(){
	int n, c, d, x, y, bw, bh;
	cin >> w >> h >> xs >> ys >> xg >> yg >> n;
	for (int i = 0; i < n; i++){
		cin >> c >> d >> x >> y;
		if (d == 0){
			bw = 4;
			bh = 2;
		}
		else{
			bw = 2;
			bh = 4;
		}
		for (int j = 0; j < bh; j++){
			for (int k = 0; k < bw; k++){
				stage[y + j][x + k] = c;
			}
		}
	}
	bc = stage[1][1];
	func(1, 1);
	if (ans == true) cout << "OK\n";
	else cout << "NG\n";
	return 0;
}

C++: #define _USE_MATH_DEFINES
#define INF 10000000
#include <iostream>
#include <sstream>
#include <cmath>
#include <algorithm>
#include <queue>
#include <stack>
#include <limits>
#include <map>
#include <string>
#include <cstring>
#include <set>
#include <deque>
#include <bitset>
#include <list>

using namespace std;

typedef long long ll;
typedef pair<int,int> P;

static const double eps = 1e-8;

int moveTo[][2] = {{-1,0},{1,0},{0,-1},{0,1}};

int stage[100][100];

void paint(int c,int d,int x,int y){
	//c:1~5 d: 0:horizonal 1:vertical
	if(d==0){
		for(int i=x;i<x+4;i++){
			for(int j=y;j<y+2;j++){
				stage[j][i] = c;
			}
		}
	}
	else{
		for(int i=x;i<x+2;i++){
			for(int j=y;j<y+4;j++){
				stage[j][i] = c;
			}
		}
	}
}

bool bfs(int w, int h, int xs, int ys, int xg, int yg){
	int cs = stage[ys][xs];
	int cg = stage[yg][xg];
	if(cs != cg) return false;

	queue<P> que;
	que.push(P(xs,ys));

	while(!que.empty()){
		int sx = que.front().first;
		int sy = que.front().second;
		
		if(sx == xg && sy == yg) return true;
		que.pop();

		stage[sy][sx] = -1;

		for(int i=0;i<4;i++){
			int dx = sx + moveTo[i][0];
			int dy = sy + moveTo[i][1];

			if(dx < 0 || dx >= w || dy < 0 || dy >= h) continue;
			if(stage[dy][dx] != cs || stage[dy][dx] == -1) continue;
			que.push(P(dx,dy));

		}

	}
	return false;
}

int main(){
	int w,h;
	while(~scanf("%d %d",&w,&h)){
		if(w==h && h==0) break;
		memset(stage,-1,sizeof(stage));
		int xs,ys;
		scanf("%d %d",&xs,&ys);

		int xg,yg;
		scanf("%d %d",&xg,&yg);

		int n;
		scanf("%d",&n);
		for(int i=0;i<n;i++){
			int c,d,x,y;
			//c:1~5 d: 0:horizonal 1:vertical
			scanf("%d %d %d %d",&c,&d,&x,&y);
			paint(c,d,x-1,y-1);
		}

		printf("%s\n",bfs(w,h,xs-1,ys-1,xg-1,yg-1) ? "OK" : "NG");
	}
}