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<cstdio>
#include<iostream>
#include<string>
#include<string.h>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<stdlib.h>
#include<queue>
#include<map>
#include<vector>
#include<list>
#include<stack>
#include<functional>
 
using namespace std;
 
#define all(c) (c).begin(), (c).end()
#define rep(i,n) for(int i=0;i<n;i++)

 
const int INF=100000000;
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0-1};
 
typedef pair<int ,int > P;
 
char maze[105][105];
 
int sx,sy;
int gx,gy;
int w,h;
 
char sc;        //スタート地点のカラー
 
//stdin
//stdout
 
void dfs(int x,int y)
{
    maze[y][x]='9';
 
    rep(i,4)
    {
/*        for(int j=-1;j<=1;j++)
        {*/
            int nx=x+dx[i];
            int ny=y+dy[i];
 
            if(0<=nx && nx<=w && 0<=ny && ny<=h &&maze[ny][nx]==sc)
            {
                dfs(nx,ny);
            }
 
/*        }*/
    }
    return ;
}
 
void solve()
{
 
    rep(i,101)
        rep(j,101)
        maze[i][j]='0';
 
    int n;
    char c;
    int d;
    int x,y;
 
    cin>>sx>>sy;
    cin>>gx>>gy;
 
    cin>>n;
 
    rep(i,n)
    {
        cin>>c>>d>>x>>y;
 
        if(d==1)
        {
            rep(i,2)
            {
                rep(j,4)
                {
                    maze[y+j][x+i]=c;
 
                }
            }
        }
        else if (d==0)
        {
            rep(i,4)
            {
                rep(j,2)
                {
                    maze[y+j][x+i]=c;
 
                }
            }
        }
 
    }
//6 6
//1 1
//3 6
//2
//1 0 1 1
//1 1 3 3
//  rep(i,w+1)
//  {
//      rep(j,h+1)
//      {
//          cout<<maze[i][j];
//
//      }
//      cout<<endl;
//  }
//
//  cout<<maze[gx][gy]<<endl;
 
    if(maze[sy][sx]=='0')
    {
        cout<<"NG"<<endl;
        return;
    }
    else
    {
        sc=maze[sy][sx];
        dfs(sx,sy);
    }
     
    //rep(i,w+1)
    //{
    //  rep(j,h+1)
    //  {
    //      cout<<maze[i][j];
 
    //  }
    //  cout<<endl;
    //}
 
    if(maze[gy][gx]=='9')
    {
        cout<<"OK"<<endl;
        return;
    }
    else
    {
        cout<<"NG"<<endl;
        return;
    }
 
 
 
}
 
int main()
{
 
    while(cin>>w>>h)
    {
        if(w==0 && h==0)
        {
            return 0;
        }
        else
        {
            solve();
        }
    }
 
 
    return 0;
}

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 = 10;
        break;
      }else if(i == n-1){
        ca = 0;
      }
    }
    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;
  }
  }
}

C++: #include<stdio.h>
#include<algorithm>
#include<functional>
int w,h;
int xs,ys,xg,yg;
int n;
int c,d,x,y;
int map[101][101];
int flg=0,temp;
void func(int ,int);
using namespace std;
int main(void){
	while(1){
		scanf("%d %d",&w,&h);
		if(w==0 && h==0){
			break;
		}
		int i,j,k;
		for(i=1;i<=100;i++){
			for(j=1;j<=100;j++){
				map[i][j]=0;
			}
		}
		scanf("%d %d %d %d %d",&xs,&ys,&xg,&yg,&n);
		for(i=0;i<n;i++){
			scanf("%d %d %d %d",&c,&d,&x,&y);
			if(d==0){
				for(k=0;k<=1;k++){
					for(j=0;j<=3;j++){
						map[y+k][x+j]=c;
					}
				}
			}
			if(d==1){
				for(k=0;k<=3;k++){
					for(j=0;j<=1;j++){
						map[y+k][x+j]=c;
					}
				}
			}
			/*for(j=1;j<=10;j++){
				for(k=1;k<=10;k++){
					printf("%d ",map[j][k]);
				}
				printf("\n");
			}
			printf("\n");*/
		}
		flg=0;
		if(map[ys][xs]==map[yg][xg] && map[ys][xs]!=0){
			temp=map[ys][xs];
			map[ys][xs]=0;
			func(ys,xs);
		}/*
		for(i=1;i<=10;i++){
			for(j=1;j<=10;j++){
				printf("%d ",map[i][j]);
			}
			printf("\n");
		}*/
		if(flg==1){
			printf("OK\n");
		}
		else {
			printf("NG\n");
		}
	}
	return 0;
}
void func(int yy,int xx){
	int dy[4]={0,1,0,-1},dx[4]={1,0,-1,0};
	int i;
	if(flg==0){
		for(i=0;i<4;i++){
			yy=yy+dy[i];
			xx=xx+dx[i];
			if(yy<=h && yy>=1 && xx<=w && xx>=1 && map[xx][yy]==temp){
				map[yy][xx]=0;
				if(xg==xx && yg==yy){
					flg=1;
					break;
				}
				func(yy,xx);
			}
		}
	}
}