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 <cstring>
#include <cstdlib>
#include <cmath>
#include <complex>
#include <string>
#include <sstream>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <functional>
#include <iostream>
#include <map>
using namespace std;
typedef pair<int,int> P;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-9
#define INF 2000000000
#define sz(x) ((int)(x).size())
#define fi first
#define sec second
#define SORT(x) sort((x).begin(),(x).end())
#define all(x) (x).begin(),(x).end()
#define EQ(a,b) (abs((a)-(b))<eps)
int w,h;
int sx,sy,gx,gy;
int n;
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};
bool used[120][120];
int f[120][120];
void set(int c,int d,int x,int y)
{
	if(d==0)
	{
		for(int i=0;i<2;i++)
		{
			for(int j=0;j<4;j++)
			{
				f[x+i][y+j]=c;
			}
		}
	}
	else
	{
		for(int i=0;i<4;i++)
		{
			for(int j=0;j<2;j++)
			{
				f[x+i][y+j]=c;
			}
		}
	}
	return;
}
bool judge()
{
	if(f[sx][sy]!=f[gx][gy])return false;
	memset(used,false,sizeof(used));
	queue<P> q;
	q.push(mp(sx,sy));
	used[sx][sy]=true;
	while(!q.empty())
	{
		P a=q.front();
		q.pop();
		for(int i=0;i<4;i++)
		{
			int nx=a.fi+dx[i],ny=a.sec+dy[i];
			if(nx<=0||nx>w||ny<=0||ny>h)continue;
			if(used[nx][ny]||f[nx][ny]!=f[a.fi][a.sec])continue;
			if(nx==gx&&ny==gy)return true;
			used[nx][ny]=true;
			q.push(mp(nx,ny));
		}
	}
	return false;
}
int main()
{
	while(1)
	{
		memset(f,0,sizeof(f));
		scanf("%d %d",&h,&w);
		if(w==0&&h==0)break;
		scanf("%d %d",&sy,&sx);
		scanf("%d %d",&gy,&gx);
		scanf("%d",&n);
		for(int i=0;i<n;i++)
		{
			int c,d,x,y;
			scanf("%d %d %d %d",&c,&d,&y,&x);
			set(c,d,x,y);
		}
		if(judge())puts("OK");
		else puts("NG");
	}
	return 0;
}

C++: #include<iostream>

using namespace std;
int board[100][100];
bool memo[100][100];
int w, h;

void judge(int x, int y, int c){
  if(x<0 || y<0 || x>=w || y>=h)return;
  if(board[y][x]!=c)return;
  if(memo[y][x])return;
  memo[y][x] = 1;
  judge(x-1, y, c);
  judge(x+1, y, c);
  judge(x, y-1, c);
  judge(x, y+1, c);
  return;
}
int main(){
  int xs, ys, xg, yg, n, i, j, k, c, d, x, y;
  while(cin>> w >> h, w+h){
    for(i=0; i<100; i++){
      for(j=0; j<100; j++){
        board[i][j] = 0;
      }
    }
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;
    for(i=0; i<n; i++){
      cin >> c >> d >> x >> y;
      if(d==0){
        for(j=y-1; j<y+1; j++){
          for(k=x-1; k<x+3; k++){
            board[j][k] = c;
          }
        }
      }else{
        for(j=y-1; j<y+3; j++){
          for(k=x-1; k<x+1; k++){
            board[j][k] = c;
          }
        }
      }
    }
    judge(xs-1, ys-1, board[ys-1][xs-1]);
    if(memo[yg-1][xg-1]==1){
      cout << "OK" << endl;
    }else{
      cout << "NG" << endl;
    }
  }
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
#define INF 1010001000
#define loop(i, n) for (int i = 0; i < n; i++)
#define mp make_pair
typedef pair<int, int> i_i;

int sx, sy, gx, gy;
int n, m; 

int main()
{

while(cin >> n >> m,(n|m)){
 m++; n++;
 vector<vector<int> > graph(m,vector<int>(n,0));
 
 cin>>sx>>sy>>gx>>gy;
 int bl;  cin>>bl;
 loop(i, bl){
  int a,b,c,t; cin>>a>>b>>c>>t;
  if(b){
   for(int j=t;j<t+2;j++){
    for(int k=c;k<c+4;k++){
     graph[k][j] = a;
    }
   } 
  } else {
   for(int j=c;j<c+2;j++){
    for(int k=t;k<t+4;k++){
     graph[k][j] = a;
    }
   }
  }
 }
cout<<(dfs(graph))?"OK":"NG"<<endl;
}
return 0;
}

bool dfs(vector<vector<int> > &g) {
int cl = g[sx][sy];
vector<vector<bool> > vsed(m,vector<bool>(n,false));
queue<i_i > q;
q.push(mp(sx,sy));
while(!q.empty()){
int x = q.top().first, y = q.top().second;
q.pop();
if(x == gx && y == gy){
return true;
}
if(vsed[x][y]){
continue;
} else {
vsed[x][y]=true;
}

loop(i, 4) {
int nx = x +dx[i], ny = y +dy[i];
if(0<nx && nx < n && 0<ny && ny < m){
if(g[nx][ny] == cl){
q.push(mp(nx,ny));
}
} 
}

}
return false;
}