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 <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;

int show=0;
int w,h,sx,sy,gx,gy,d[101][101],dx[4]={1,0,-1,0},dy[4]={0,1,0,-1},C;
int field[101][101];
const int INF=9999999;
typedef pair<int,int> P;

void bfs(){
	queue<P> que;
	for(int i=1;i<=h;i++)for(int j=1;j<=w;j++)d[i][j]=INF;
	que.push(P(sy,sx));
	d[sy][sx]=0;
	while(!que.empty()){
		P p=que.front(); que.pop();
		if(p.first==gy&&p.second==gx)break;
		for(int i=0;i<4;i++){
			int ny=p.first+dy[i],nx=p.second+dx[i];
			if(1<=ny&&ny<=h&&1<=nx&&nx<=w&&field[ny][nx]==C&&d[ny][nx]==INF){
			que.push(P(ny,nx));
			d[ny][nx]=d[p.first][p.second]+1;
			}
		}
	}
	if(d[gy][gx]==INF)cout<<"NG"<<endl;
	else cout<<"OK"<<endl;
}

int main() {
	while(cin>>w>>h){
		if(!h)return 0;
		int n,c,di,x,y;
		cin>>sx>>sy>>gx>>gy>>n;
		for(int i=1;i<=h;i++)for(int j=1;j<=w;j++)field[i][j]=0;
		for(int i=0;i<n;i++){
			cin>>c>>di>>x>>y;
			for(int j=y;j<y+2+di*2;j++)for(int k=x;k<x+2+!di*2;k++)field[j][k]=c;
		}
		C=field[sy][sx];
		if(!C)cout<<"NG"<<endl;
		else bfs();
		if(show){
			for(int i=1;i<=h;i++){for(int j=1;j<=w;j++){if(field[i][j])cout<<field[i][j];else cout<<" ";}cout<<endl;}
			for(int i=1;i<=h;i++){for(int j=1;j<=w;j++){if(d[i][j]<INF)cout<<d[i][j]<<" ";else cout<<"  ";}cout<<endl;}
		}
	}
}

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

int Board[102][102];    //Board[j, x, w][i, y, h]
bool isOK;
int xs, ys, xg, yg;

void DFS(int c, int x, int y){
    if(Board[x][y] != c){
        return;
    }
    else if(x==xg && y==yg){
        isOK = true;
        return;
    }

    Board[x][y] = 0;

    DFS(c, x+1, y  );
    DFS(c, x  , y+1);
    DFS(c, x-1, y  );
    DFS(c, x  , y-1);
}

// void Showboard(int w, int h){
//     for(int i=0;i<=h;i++){
//         for(int j=0;j<=w;j++)
//             cout << Board[j][i] << " ";
//         cout << endl;
//     }
//     cout << endl;
// }

int main(){
    int w,h;
    while(true){
        cin >> w >> h;
        if(w==0 && h==0)
            break;
        
        isOK = false;
        for(int i=0;i<102;i++){
            for(int j=0;j<102;j++)
                Board[j][i] = 9;
        }
        cin >> xs >> ys >> xg >> yg;

        int n, c, d, x, y;
        cin >> n;
        for(int t=0;t<n;t++){
            cin >> c >> d >> x >> y;
            int wb = 2+(!d*2);  
            int hb = 2+(d*2);
            for(int i=0;i<hb;i++){
                for(int j=0;j<wb;j++)
                    Board[x+j][y+i] = c;
            }
        }

        // Showboard(w, h);

        DFS(Board[xs][ys], xs, ys);

        // Showboard(w, h);

        if(isOK)
            cout << "OK" << endl;
        else
            cout << "NG" << endl;

    }

    return 0;
}

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

int w, h, xs, ys, xg, yg, n;
int b[101][101];
bool f[101][101];

void maze(int x, int y) {
	f[x][y] = 1;

	int cl = b[xs][ys];

	if (x < w && !f[x + 1][y] && b[x + 1][y] == cl)
		maze(x + 1, y);

	if (x > 1 && !f[x - 1][y] && b[x - 1][y] == cl)
		maze(x - 1, y);

	if (y < h && !f[x][y + 1] && b[x][y + 1] == cl)
		maze(x, y + 1);

	if (y > 1 && !f[x][y - 1] && b[x][y - 1] == cl)
		maze(x, y - 1);
}

int main()
{
	cin >> w >> h;

	while (w != 0 || h != 0) {
		cin >> xs >> ys >> xg >> yg >> n;

		memset(b, 0, sizeof(b));
		memset(f, 0, sizeof(f));

		for (int i = 0; i < n; i++) {
			int c, d, x, y;

			cin >> c >> d >> x >> y;

			if (d) {
				for (int i = 0; i < 2; i++)
					for (int j = 0; j < 4; j++)
						b[x + i][y + j] = c;
			}
			else {
				for (int i = 0; i < 2; i++)
					for (int j = 0; j < 4; j++)
						b[x + j][y + i] = c;
			}
		}

		maze(xs, ys);

		if (f[xg][yg])
			cout << "OK" << endl;
		else
			cout << "NG" << endl;

		cin >> w >> h;
	}

	return 0;
}

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

int F[102][102];

void DFS(int Y,int X,int C){
   if(F[Y][X]!=C)
      return;
   F[Y][X]=6;
   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,xg,yg,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=1;i<=n;i++){
         cin >> c >> d >> x >> y;
         if(d==0){
             F[y+1][x+1]=c;
             F[y+1][x+2]=c;
             F[y+1][x+3]=c;
             F[y+1][x+4]=c;  
             F[y+2][x+1]=c;
             F[y+2][x+2]=c;
             F[y+2][x+3]=c;
             F[y+2][x+4]=c;   
         }
         else{
             F[y+1][x+1]=c;
             F[y+2][x+1]=c;
             F[y+3][x+1]=c;
             F[y+4][x+1]=c;  
             F[y+1][x+2]=c;
             F[y+2][x+2]=c;
             F[y+3][x+2]=c;
             F[y+4][x+2]=c;   
         }
      }
      if(F[ys+1][xs+1]!=1&&F[ys+1][xs+1]!=2&&F[ys+1][xs+1]!=3&&F[ys+1][xs+1]!=4&&F[ys+1][xs+1]!=5)
         cout << "NG" << endl;
      else
         DFS(ys+1,xs+1,F[ys+1][xs+1]);
      if(F[yg+1][xg+1]==F[ys+1][xs+1])
         cout << "OK" << endl;
      else
         cout << "NG" << endl;
      for(int i=1;i<=w;i++)
         for(int j=1;j<=h;j++)
            F[i][j]=0;
      
   }
   return 0;
}