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 <stdio.h>
#include <iostream>
#include <math.h>
#include <numeric>
#include <vector>
#include <map>
#include <functional>
#include <stdio.h>
#include <array>
#include <algorithm>
#include <string>
#include <assert.h>
#include <stdio.h>
#include <queue>
#include<iomanip>
#include<bitset>
#include<list>
using namespace std;

const int mod = 1000000007;

struct Mod {
	int num;
	Mod() : num(0) { ; }
	Mod(int n) : num((n % mod + mod) % mod) { ; }
	operator int() { return num; }
};

Mod operator+(Mod a, Mod b) { return Mod((a.num + b.num) % mod); }
Mod operator-(Mod a, Mod b) { return Mod((mod + a.num - b.num) % mod); }
Mod operator*(Mod a, Mod b) { return Mod(((long long)a.num * b.num) % mod); }
Mod operator+=(Mod &a, Mod b) { return a = a + b; }
Mod operator-=(Mod &a, Mod b) { return a = a - b; }
Mod operator*=(Mod &a, Mod b) { return a = a * b; }
Mod operator^(Mod a, int n) {
	if (n == 0) return Mod(1);
	Mod res = (a * a) ^ (n / 2);
	if (n % 2) res = res * a;
	return res;
}
Mod inv(Mod a) { return a ^ (mod - 2); }
Mod operator/(Mod a, Mod b) { 
assert(b!=0);
return a * inv(b);
 }

#define MAX_N 1024000

Mod fact[MAX_N], factinv[MAX_N];
void init() {
	fact[0] = Mod(1); factinv[0] = 1;
	for (int i = 0; i < MAX_N - 1; ++i) {
		fact[i + 1] = fact[i] * Mod(i + 1);
		factinv[i + 1] = factinv[i] / Mod(i + 1);
	}
}
Mod comb(int a, int b) {
	return fact[a] * factinv[b] * factinv[a - b];
}

#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()


int dx[4] = { -1,0,1,0 };
int dy[4] = { 0,-1,0,1 };
struct Node {
	Node(int a, int b, int c) {
		time = a;
		x = b;
		y = c;
	}
	int time;
	int x;
	int y;
};
class Compare {
public:
	bool operator()(const Node& l, const Node& r) {
		return l.time < r.time;
	}
};


int main() {
	while(1) {
		int w, h;
		cin >> w >> h;
		if (!w)return 0;
		vector<vector<int>> maze(h+2, vector<int>(w+2,0));

		int xs, ys, xg, yg;
		cin >> xs >> ys >> xg >> yg;
		int n;
		cin >> n;
		for (int i = 0; i < n; ++i) {
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			if (!d) {
				for (int ax = 0; ax < 4; ++ax) {
					for (int ay = 0; ay < 2; ++ay) {
						maze[y+ay][x+ax] = c;
					}
				}
			}
			else {
				for (int ax = 0; ax < 2; ++ax) {
					for (int ay = 0; ay < 4; ++ay) {
						maze[y + ay][x + ax] = c;
					}
				}
			}
		}
		int color = maze[ys][xs];
		if (!color) {
			cout << "NG" << endl;
			continue;
		}
		vector<vector<bool>>times(h, vector<bool>(w, false));

		priority_queue<Node,vector<Node>,Compare> qu;
		 qu.emplace(0,xs,ys);
		 bool flag=false;
		while (!qu.empty()) {
			Node an(qu.top());
			qu.pop();
			if (an.x == xg&&an.y == yg) {
				flag = true;
				break;
			}
			else {
				for (int i = 0; i < 4; ++i) {
					if (maze[an.y + dy[i]][an.x + dx[i]] == color) {
						if (times[an.y + dy[i]][an.x + dx[i]]) {

						}
						else {
							qu.push(Node{ an.time + 1,an.x + dx[i], an.y + dy[i] });
							times[an.y + dy[i]][an.x + dx[i]] = true;
						}
						
					}
				}
			}
		}
		if (flag) {
			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 A)
{
  if (F[Y][X] != A)
    return;

  F[Y][X] = 7;

  DFS (Y - 1, X, A);
  DFS (Y, X + 1, A);
  DFS (Y + 1, X, A);
  DFS (Y, X - 1, A);
}

int
main ()
{
  int w, h;
  int xs, ys;
  int xg, yg;
  int n;
  int c, d, x, y;

  while (true)
    {
      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;
	  if (d == 0)
	    {
	      for (int a = 0; a < 4; a++)
		{
		  for (int b = 0; b < 2; b++)
		    {
		      F[y + b][x + a] = c;
		    }
		}

	    }
	  else
	    {
	      for (int a = 0; a < 2; a++)
		{
		  for (int b = 0; b < 4; b++)
		    {
		      F[y + b][x + a] = c;
		    }
		}
	    }

	}


      if (F[ys][xs] == 1 || F[ys][xs] == 2 || F[ys][xs] == 3
	  || F[ys][xs] == 4 || F[ys][xs] == 5)
	{
	  DFS (ys, xs, F[ys][xs]);
	}

      if (F[yg][xg] == F[ys][xs])
	{
	  cout << "OK" << endl;
	}
      else
	{
	  cout << "NG" << endl;
	}

    /*for (int y = 0; y < h; y++)
	{
	  for (int x = 0; x < w; x++)
	    {
	      cout << F[y][x];
	    }
         cout << endl;
	}*/

    }

  return 0;
}

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

int a[102][102],color;

void dfs(int x,int y){
   
    a[y][x] = 9;
    
    if(a[y+1][x] == color){
      dfs(x,y+1);
    }
    if(a[y][x+1] == color){
      dfs(x+1,y);
    }
    if(a[y-1][x] == color){
      dfs(x,y-1);
    } 
    if(a[y][x-1] == color){
      dfs(x-1,y);
    }
 
} 

int main(){

  int xs,ys,xg,yg,n,c,d,x,y,w,h;

  while(1){
  
    cin >>w>>h;
    
    if(w == 0 && h == 0)break;

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

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

    cin >>n;

    for(int i = 0 ; i < n ; i++){
      
      cin >> c >> d >> x >> y;
      
      if( d == 0 ){
	for(int i = 0 ; i < 2 ; i++){
	  for(int j = 0 ; j < 4 ; j++){
	    a[i+y][j+x] = c;
	  }
	}
      }else{
	for(int i = 0 ; i < 4 ; i++){
	  for(int j = 0 ; j < 2 ; j++){
	    a[i+y][j+x] = c;
	  }
	}
      }
    
    }
    
    /*
      for(int i = 0 ; i < h+2 ; i ++){
      for(int j = 0 ; j < w+2 ; j++){
      cout << a[i][j];
      }
      cout <<endl;
      }
      cout <<endl;
    */
  
    if(a[ys][xs] != 0){
      color = a[ys][xs];
      dfs(xs,ys);
    }
    
    /*
      for(int i = 0 ; i < h+2 ; i ++){
      for(int j = 0 ; j < w+2 ; j++){
      cout << a[i][j];
      }
      cout <<endl;
      }
    */
    
    if(a[yg][xg] == 9){
      cout <<"OK"<<endl;
    }else{
      cout <<"NG"<<endl;
    }
    
  }      
  
  return 0;
  
}