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 <bits/stdc++.h>
using namespace std;
  
// #define int long long
#define pb push_back
  
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vector<int> > vii;
 
template <class X> void print(X Target){ cout << Target << '\n'; }

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

int w, h;
int xs, ys, xg, yg;
int mp[128][128];
bool check[128][128];

void dfs(int y, int x, int color)
{
  if (x < 1 || x > w || y < 1 || y > h) return;
  if (check[y][x]) return;
  check[y][x] = true;
  for (int i = 0; i < 4; i++){
    if (mp[y + dy[i]][x + dx[i]] == color){
      dfs(y + dy[i], x + dx[i], color);
    }
  }
}

signed main()
{
  ios::sync_with_stdio(false);
  int n;

  while (cin >> w >> h, w || h){
    memset(field, false, sizeof(check));
    memset(mp, 0, sizeof(mp));
    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){
        for (int j = 0; j < 4; j++){
          for (int k = 0; k < 2; k++){
            mp[y + j][x + k] = c;
          }
        }
      }
      else {
        for (int j = 0; j < 2; j++){
          for (int k = 0; k < 4; k++){
            mp[y + j][x + k] = c;
          }
        }
      }
    }
    dfs(ys, xs, mp[ys][xs]);
    (check[yg][xg]) ? print("OK") : print("NG");
  }

  return (0);
}

C++: #include<map>
#include<queue>
#include<stdio.h>
#include<iostream>
#include<algorithm>
#define SIZE 110
using namespace std;

typedef pair<int,int> P;

void solve(void);       //処理

int n;             //ブロックの個数
int w,h;           //ボードの幅、高さ
int goal;          //迷路になっているか
int scolor;        //スタート位置の色
int sx,sy,gx,gy;   //スタートの座標、ゴールの座標
int mass[SIZE][SIZE];
int data[SIZE][SIZE];
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int c[SIZE],d[SIZE],x[SIZE],y[SIZE];       //ブロックの色、向き、左上の座標


int main(){

  int i,j;             //カウンタ変数

  while(1){

    goal=0;

    /*情報の入力*/
    cin>>w>>h;

    if(w==0 && h==0)break;
    
    cin>>sx>>sy;
    cin>>gx>>gy;  
    cin>>n;
    
    for(i=0;i<n;i++){
      cin>>c[i]>>d[i]>>x[i]>>y[i];
      
    }

  memset(mass,0,sizeof(mass));

  /*マスの作成*/
  for(i=0;i<n;i++){
    if(d[i]==0){       //横向きなら
      for(j=0;j<4;j++){
	mass[y[i]][x[i]+j]=c[i];
	mass[y[i]+1][x[i]+j]=c[i];
      }
    }
    else if(d[i]==1){              //縦向きなら
      for(j=0;j<4;j++){
	mass[y[i]+j][x[i]]=c[i];
	mass[y[i]+j][x[i]+1]=c[i];
      }
    }
  }
  
  scolor=mass[sy][sx];

  if(scolor==mass[gy][gx]){
  
    solve();
     
    if(goal==1){
      cout<<"OK"<<endl;
    } else {
      cout<<"NG"<<endl;
      }
  }
  else {
    cout<<"NG"<<endl;
  }

  }
  
  return 0;
}
void solve(void){
  
  int i,j;
  queue<P> que;
  memset(data,-1,sizeof(data));
  que.push(P(sy,sx));     //queにスタート位置の座標を格納
  data[sy][sx]=0;
  
  while(!que.empty()){    //queが空でない間
    P p=que.front();
    que.pop();
    
    if(p.first==gy && p.second==gx){
      goal=1;
      break;
    }
    for(i=0;i<4;i++){
      int ny=p.first+dy[i];
      int nx=p.second+dx[i];
      if(nx>=0 && nx<w && ny>=0 && ny<h && mass[ny][nx]==scolor && data[ny][nx]==-1){
	que.push(P(ny,nx));
	data[ny][nx]=1;
      }
    }
  }
  return;
}

C++: #include<stdio.h>
#include<string.h>
void haichi(void);
void Block(int,int);
int c,d,x,y,xg,yg,M,Flag;
int MAP[101][101],MF[101][101];
int main(void)
{
	int w,h,xs,ys,n;
	while(1){
		Flag=0;
		memset(MAP,0,sizeof(MAP));
		memset(MF,0,sizeof(MF));
		scanf("%d %d",&w,&h);
		if(w == 0 && h == 0) break;
		scanf("%d %d %d %d",&xs,&ys,&xg,&yg);
		scanf("%d",&n);
		for(int i=0;i<n;i++){
			scanf("%d %d %d %d",&c,&d,&x,&y);
			haichi();
		}
		/*for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				printf("%d",MAP[i][j]);
			}
			printf("\n");
		}*/
		M = MAP[ys][xs];//
		if(MAP[ys][xs] == MAP[yg][xg])
			Block(xs,ys);
		if(Flag==1)
			printf("OK\n");
		else
			printf("NG\n");
	}
	return 0;
}

void haichi(void)
{
	if(d==0){
		MAP[y][x]=c;MAP[y][x+1]=c;MAP[y][x+2]=c;MAP[y][x+3]=c;
		MAP[y+1][x]=c;MAP[y+1][x+1]=c;MAP[y+1][x+2]=c;MAP[y+1][x+3]=c;
	}
	else if(d==1){
		MAP[y][x]=c;MAP[y][x+1]=c;
		MAP[y+1][x]=c;MAP[y+1][x+1]=c;
		MAP[y+2][x]=c;MAP[y+2][x+1]=c;
		MAP[y+3][x]=c;MAP[y+3][x+1]=c;
	}
}

void Block(int X,int Y)
{
	MF[Y][X] = 1;
	//printf("%d",M);
	if(X == xg && Y == yg)
		Flag = 1;
	if(MAP[Y-1][X] == M && MF[Y-1][X] == 0) Block(X,Y-1); //???
	if(MAP[Y+1][X] == M && MF[Y+1][X] == 0) Block(X,Y+1); //???
	if(MAP[Y][X-1] == M && MF[Y][X-1] == 0) Block(X-1,Y); //???
	if(MAP[Y][X+1] == M && MF[Y][X+1] == 0) Block(X+1,Y); //???
}