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<string>
#include<vector>
#include<utility>
#include<queue>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<complex>
#define INF 2147483647
#define llINF 9223372036854775807
#define pb push_back
#define mp make_pair 
#define F first
#define S second
#define ll long long

using namespace std;
int main(){
  int w,h;
  while(cin>>w>>h,w+h){
    int xs,ys,xg,yg;
    bool Map[h+10][w+10]={};
    bool flag=false;
    cin>>xs>>ys>>xg>>yg;
    xs--;ys--;xg--;yg--;
    int n;cin>>n;
    int Map2[h+10][w+10]={};
    Map[ys][xs]=true;
    queue<pair<int,int> >que;
    que.push(mp(ys,xs));
    for(int i=0;i<n;i++){
      int c,d,x,y;
      cin>>c>>d>>x>>y;
      x--;y--;
      if(d==0){
	for(int i=y;i<y+2;i++)
	  for(int j=x;j<x+4;j++)
	    Map2[i][j]=c;
      }else if(d==1){
	for(int i=y;i<y+4;i++)
	  for(int j=x;j<x+2;j++)
	    Map2[i][j]=c;
      }
    }
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++)
	cout<<Map2[i][j]<<" ";
      cout<<endl;
    }
    int vx[4]={0,-1,0,1};
    int vy[4]={1,0,-1,0};
    while(!que.empty()){
      pair<int,int>now=que.front();
      que.pop();
      if(now.F==xg&&now.S==yg){
	flag=true;
	break;
      }
      for(int kk=0;kk<4;kk++){
	int as=now.F+vx[kk];int bs=now.S+vy[kk];
	if(as<h&&as>=0&&bs<w&&bs>=0&&Map2[now.F][now.S]==Map2[as][bs]&&!Map[as][bs]){
	  que.push(mp(as,bs));
	  Map[as][bs]=true;
	}
      }
    }
    if(flag)
      cout<<"OK"<<endl;
    else
      cout<<"NG"<<endl;
  }
  return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <set>
#include <algorithm>
#include <array>
#include <complex>
#include <utility>
#include <map>
int needleX[4] = { -1,0,1,0 };
int needleY[4] = { 0,1,0,-1 };
bool dfs(int x, int y, int goalx, int goaly, std::vector<std::vector<bool>>&canGo) {
    if (x == goalx && y == goaly) { return true; }

    canGo[x][y] = false;
    for (int i = 0; i < 4; i++) {
        int next_x = x + needleX[i];
        int next_y = y + needleY[i];

        if (canGo[next_x][next_y]) {
            bool flag = dfs(next_x, next_y, goalx, goaly, canGo);
            if (flag)
                return true;
        }
    }
    return false;
}
int main(void) {
    int h, w, n;
    std::cin >> w >> h;
    std::vector<std::string> ans;
    while(h!=0&& w!=0){
        int color, orient, leftX, leftY;
        int sx, sy, gx, gy;
        std::cin >> sx >> sy >> gx >> gy;
        std::vector<std::vector<int>> board(w + 2, std::vector<int>(h+ 2, 0));
        std::vector<std::vector<bool>> canGo(w + 2, std::vector<bool>(h + 2, false));
        std::cin >> n;
        int start = 0, goal = 0;
        for (int i = 0; i < n; i++) {
            std::cin >> color >> orient >> leftX >> leftY;


            if (orient == 0) {
                for (int j = 0; j <= 3; j++) {
                    for (int k = 0; k <= 1; k++) {
                        board[leftX + j][leftY + k] = color;
                        if (leftX + j == sx && leftY + k == sy) {
                            start = color;
                        }
                        else if (leftX + j == gx && leftY + k == gy) {
                            goal = color;
                        }
                    }
                }

            }
            else {
                for (int j = 0; j <= 1; j++) {
                    for (int k = 0; k <= 3; k++) {
                        board[leftX + j][leftY + k] = color;
                        if (leftX + j == sx && leftY + k == sy) {
                            start = color;
                        }
                        else if (leftX + j == gx && leftY + k == gy) {
                            goal = color;
                        }
                    }
                }
            }
        }
        /*for (int i = 0; i <= w; i++) {
            for (int j = 0; j <= h; j++) {
                std::cout << board[i][j] << " ";
            }
            std::cout << std::endl;
        }*/
        if (start != goal) {
            ans.push_back("NG");
            
            break;
        }
        for (int i = 0; i <= w; i++) {
            for (int j = 0; j <= h; j++) {
                if (board[i][j] == start) {
                    canGo[i][j] = true;
                }
            }
        }
        bool result = dfs(sx, sy, gx, gy, canGo);
        if (result) { ans.push_back("OK"); }
        else { ans.push_back("NG"); }
        std::cin >> h >> w;
    }
    int anssize = ans.size();
    for (int i = 0; i < anssize; i++) {
        std::cout << ans[i] << std::endl;
    }
    return 0;
}