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<algorithm>
#include<vector>
#include<string>
#pragma region defins
#define ll long long
#define loop(i,n) for (int i = 0; i < n; i++)
#define loops(i,f,n) for (int i = (f); i < n; i++)
#define INF 100000000000000
#define sort(a) sort(a.begin(),a.end())
#define rsort(a) sort(a.rbegin(),a.rend())
using namespace std;
#pragma endregion
int w, h, sx, sy, gx, gy, n;
vector <vector<int >> grid(105, vector<int>(105));
vector <vector<bool >> grid_visited(105, vector<bool>(105, false));
void input(int c, int d, int x, int y)
{
	if (d == 0)//yokonaga
	{
		loop(i, 2)
		{
			loop(j, 4)
			{
				grid[y + i][x + j] = c;
			}
		}
	}
	else//tatenaga
	{
		loop(i, 4)
		{
			loop(j, 2)
			{
				grid[y + i][x + j] = c;
			}
		}
	}
}
bool dfs(int nx, int ny)
{
	if (nx == gx&&ny == gy)return true;
	if (nx < 0 || ny < 0 || nx >= h || ny >= w || grid[nx][ny] == 0 || grid_visited[nx][ny])return false;
	grid_visited[nx][ny] = true;
	return (dfs(nx + 1, ny) || dfs(nx, ny + 1) || dfs(nx - 1, ny) || dfs(nx, ny - 1));
	return false;
}
int main()
{
	while (1)
	{
		cin >> w >> h;
		if (!w && !h) break;
		else
		{
			cin >> sx >> sy >> gx >> gy >> n;
			sx--; sy--; gx--; gy--;
			loop(i, n)
			{
				int c, d, x, y;
				cin >> c >> d >> x >> y;
				x--; y--;
				input(c, d, x, y);
			}
			/*loop(i, h)
			{
				loop(j, w)
				{
					cout << grid[i][j] << " ";
				}
				cout << endl;
			}*/
			cout << (dfs(sx, sy) ? "OK" : "NG") << endl;
		}
	}

}

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

typedef pair<int, int> P;


int w, h;
int xs, ys, xg, yg, n, c, d, x, y;
int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};

void put_b(int a[][101]) {
  int X, Y;
  if(d == 0) X = 4, Y = 2;
  else X = 2, Y = 4 ;
  for(int i = 0; i < Y; i++)
    for(int j = 0; j < X; j++)
      a[y + i][x + j] = c;
}

bool bfs(int a[][101]) {
  int cs = a[ys][xs];
  if(cs != a[yg][xg]) return false;
  queue<P> que;
  que.push(P(xs, ys));
  while(que.size()) {
    P p = que.front();
    que.pop();
    if(p.first == xg && p.second == yg) return true;
    for(int i = 0; i < 4; i++) {
      int nx = p.first + dx[i], ny = p.second +dy[i];
      if(0 <= nx && nx < w && 0 <= ny && ny < h && a[ny][nx] == cs) 
	que.push(P(nx, ny));
    }
  }
  return false;
}
int main() {
  while(cin >> w >> h, w != 0 || h != 0) {
    int a[101][101] = {};
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;
  
    while(n--) {
      cin >> c >> d >> x >> y;
      put_b(a);
    }
    /*
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++)
	cout << a[i][j];
      cout << endl;
      }*/
    if(bfs(a) == true) cout << "OK" << endl;
    else cout << "NG" << endl;
  }
  return 0;
}

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

int F[102][102];
int xg,yg;
int flag = 0;

void DFS(int Y,int X,int c){
  if(F[Y][X] != c){
    return;
  }
  if(Y == xg && X == yg){
    flag = 1;
  }

  F[Y][X] = 0;
  DFS(Y-1,X  ,c);
  //DFS(Y-1,X+1,c);
  DFS(Y  ,X+1,c);
  //DFS(Y+1,X+1,c);
  DFS(Y+1,X  ,c);
  //DFS(Y+1,X-1,c);
  DFS(Y  ,X-1,c);
  //DFS(Y-1,X-1,c);
}


int main(){
  int w,h,xs,ys,n;
  while(1){
  cin >> w >> h;
  if(w == 0 && h == 0)
    break;

  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 == 0){
      for(int j=0;j<4;j++){
        F[x+j][y] = c;
        F[x+j][y+1] = c;
      }
    } else {
      for(int j=0;j<4;j++){
        F[x][y+j] = c;
        F[x+1][y+j] = c;
      }
    }
  }

  DFS(xs,ys,F[xs][ys]);
  if(flag == 1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
}
}

C++: #include <iostream>
using namespace std;
  
int F[105][105];
int xg,yg;
  
  
void DFS(int Y,int X,int c){
  if(F[Y][X] != c){
    return;
  }
  
  F[Y][X] = -2000;
  DFS(Y-1,X  ,c);
  DFS(Y  ,X+1,c);
  DFS(Y+1,X  ,c);
  DFS(Y  ,X-1,c);
}
  
  
int main(){
  int w,h,xs,ys,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;

      
    cin >> xs >> ys >> xg >> yg >> n;
    int c[n],d[n],x[n],y[n],ca;
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
    }
    for(int i=0;i<n;i++){
      if(c[i] == 0){
        ca = 1000;
        break;
      }else if(i == n-1){
        ca = 1000;
      }
    }
    for(int i=0; i<102; i++){
          for(int j=0; j<102; j++){
            F[i][j]=ca;
          }
    }
    for(int i=0;i<n;i++){
      if(d[i] == 0){
        for(int j=0;j<4;j++){
          F[x[i]+j][y[i]] = c[i];
          F[x[i]+j][y[i]+1] = c[i];
        }
      } else {
        for(int j=0;j<4;j++){
          F[x[i]][y[i]+j] = c[i];
          F[x[i]+1][y[i]+j] = c[i];
        }
      }
    }
 
  DFS(xs,ys,F[xs][ys]);
  
  if(F[xg][yg] == -2000){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
}