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 <vector>

using namespace std;

#define repeat(n, i) for(int i=0; i<(n); i++)
int w, h;
int xs, ys;
int xg, yg;
int n;

int st_color;

vector< vector<int> > board;

#define VISITED 6

bool get_input() {
    cin >> w >> h;
    if (w == 0 && h == 0) return false;
    board.resize(h);
    repeat(h, i) board[i].resize(w);
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;
    repeat(n, i) {
        int c, d, x, y;
        cin >> c >> d >> x >> y;
        if (d == 0) {
            for (int j = y-1; j < y-1+4; j++) {
                for (int k = x-1; k < x-1+2; k++) {
                    board[j][k] = c;
                }
            }
        } else {
            for (int j = y-1; j < y-1+2; j++) {
                for (int k = x-1; k < x-1+4; k++) {
                    board[j][k] = c;
                }
            }
        }
    }
    st_color = board[ys-1][xs-1];
    return true;
}

int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, -1, 1};

bool possible;
void dfs(int x, int y) {
    board[y-1][x-1] = VISITED;
    if (x == xg && y == yg) {
        possible = true;
        return;
    }
    repeat(4, i) {
        int nx = x+dx[i], ny = y+dy[i];
        if (1 <= nx && nx <= w && 1 <= ny && ny <= h) {
            if (board[ny-1][nx-1] != VISITED) {
                dfs(nx, ny);
            }
        }
    }
}

void solve() {
    possible = false; dfs(xs, ys);
    if (possible) cout << "OK" << endl;
    else cout << "NG" << endl;
}

int main() {
    while (get_input()) {
        solve();
    }
    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
int w,h,xg,yg,n,ans = 0;
int mas[110][110];
int dx[4] = {0,-1,0,1};
int dy[4] = {1,0,-1,0};
void block(int x, int y, int m);
int main(){
  int c,d,x,y,xs,ys;
  while(1){
    memset(mas,0,sizeof(mas));
    ans = 0;
    scanf("%d %d",&w,&h);
    if(w == 0 && h == 0)break;
    scanf("%d %d",&xs,&ys);
    scanf("%d %d",&xg,&yg);
    scanf("%d",&n);
    for(int u = 0; u < n; u++){
      cin >> c >> d >> x >> y;
      if(d == 0){
	for(int i = y; i < y + 2; i++){
	  for(int j = x; j < x + 4; j++){
	    mas[i][j] = c;
	  }
	}
      }
      else {
	for(int i = y; i < y + 4; i++){
	  for(int j = x; j < x + 2; j++){
	    mas[i][j] = c;
	  }
	}
      }
    }
    if(mas[ys][xs] != 0){
      block(xs,ys,mas[ys][xs]);
    }
    if(ans == 1)cout << "OK" << endl;
    else cout << "NG" << endl;
  }
}

void block(int x, int y, int m){
  if(x == xg && y == yg){
    ans = 1;
    return ;
  }
  mas[y][x] = 0;
  for(int i = 0; i < 4; i++){
    int nx = x + dx[i];
    int ny = y + dy[i];
    if(mas[ny][nx] == m && nx <= w && nx > 0 && ny <= h && ny > 0 && mas[ny][nx] != 0){
      block(nx,ny,mas[ny][nx]);
    }
  }
}

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


int F[500][500];

//?????????????????????
void r(int yy,int xx,int z){
 if(F[yy][xx]!=z){
	return ;
 }

F[yy][xx]=10;

r(yy-1,xx,z);
r(yy,xx+1,z);
r(yy+1,xx,z);
r(yy,xx-1,z);

}

void yoko(int c,int x,int y){
 F[x  ][y]=c;
 F[x+1][y]=c;
 F[x+2][y]=c;
 F[x=3][y]=c;
 F[x  ][y+1]=c;
 F[x+2][y+1]=c;
 F[x+3][y+1]=c;
 F[x+4][y+1]=c;
return ;
}
void tate(int c,int x,int y){
 F[x][y  ]=c;
 F[x][y+1]=c;
 F[x][y+2]=c;
 F[x][y+3]=c;
 F[x+1][y  ]=c;
 F[x+1][y+1]=c;
 F[x+1][y+2]=c;
 F[x+1][y+3]=c;
return ;
}

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

while(1){
 cin>>w>>h;

//?????????????????????0???????????????
 if(w==0&&h==0)break;
//???????????????????????????????????\?????°????±??????£???????????????
 cin>>xs>>ys>>xg>>yg>>n;
 
//n?????°???????????????????????????
for(int i=0;i<n;i++){
	cin>>c,d,x,y;//?????????????????¨????????±????????????
	if(d==0)yoko(c,x,y);
	if(d==1)tate(c,x,y);
}

//??\????????????????????????

//??????????????????
r(xs,ys,F[xs][ys]);
//??´???????????????
if(F[xg][yg]==10){
	cout<<"OK"<<endl;
}else{
	cout<<"NG"<<endl;
}
//?????????????????????
}
return 0;
}

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

struct board{
  int mass[102][102];
};

bool goal_flag;
void DFS(int x,int y,int gx,int gy,board b,int c){
    if(b.mass[y][x]!=c)return;
    if(!b.mass[y][x])return;
    b.mass[y][x]=-1;
    if(x==gx&&y==gy)goal_flag=true;
    DFS(x+1,y,gx,gy,b,c);
    DFS(x-1,y,gx,gy,b,c);
    DFS(x,y+1,gx,gy,b,c);
    DFS(x,y-1,gx,gy,b,c);
}

int main(){
  while(1){
    int h,w;
    int start_x,start_y;
    int goal_x,goal_y;
    int n;

    cin>>w>>h;
    if(w==0&&h==0)break;
    cin>>start_x>>start_y;
    cin>>goal_x>>goal_y;
    cin>>n;

    board b;
    for(int i=0;i<102;i++){
      for(int j=0;j<102;j++){
          b.mass[i][j]=0;
        }
      }

    int c,d,x,y;
    for(int i=0;i<n;i++){
        cin>>c>>d>>x>>y;
        for(int j=0;j<2;j++){
          for(int k=0;k<4;k++){
            if(d==0){b.mass[y+j][x+k]=c;}
            else if(d==1){b.mass[y+k][x+j]=c;}
          }
        }
    }
    goal_flag=false;
    DFS(start_x,start_y,goal_x,goal_y,b,b.mass[start_y][start_x]);
    if(goal_flag)cout<<"OK";
    else cout<<"NG";
    cout<<endl;
  }
}