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<map>
#include<queue>
#include<cstdio>
#include<cstring>
#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
#define SIZE 110
using namespace std;

typedef pair<int,int> P;

void make_mass(void);   //マス作成用関数
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){

    /*情報の入力*/
    cin>>w>>h;

    if(w==h && w==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];
      
    }
    
    make_mass();

    solve();
     
    if(goal==1){
      cout<<"OK"<<endl;
      goal=0;
    } else {
      cout<<"NG"<<endl;
      }
  }
  
  return 0;
}
void make_mass(void){
  
  int i,j;

  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];
      }
    }
    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];

  
  return;
}
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){
	que.push(P(ny,nx));
	data[ny][nx]=1;
      }
    }
  }
  return;
}

C++: #include <iostream>
#include <stdio.h>
#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <queue>
#include <algorithm>
#include <set>
#include <math.h>
#include <utility>
#include <stack>
#include <string.h>
#include <complex>
using namespace std;
typedef pair<int,int> P;
const int INF = 1<<29;

const int dx[] = {0,0,1,-1};
const int dy[] = {1,-1,0,0};
int field[100][100];

int w,h;
int xs,ys,xg,yg;

bool dfs(int y,int x){
    if(field[y][x]==0) return false;
    if(y==yg && x==xg) return true;
    int c = field[y][x];
    field[y][x] = 0;
    for(int i=0;i<4;i++){
        int nextx = x+dx[i], nexty = y+dy[i];
        if(0<=nextx&&nextx<w&&0<=nexty&&nexty<h && c==field[nexty][nextx]){
            if(dfs(nexty,nextx)) return true;
        }
    }
    return false;
}

int main(){
    while(1){
        scanf("%d%d",&w,&h);
        if(w==0)break;

        scanf("%d%d%d%d",&xs,&ys,&xg,&yg);
        xs--;ys--;xg--;yg--;

        int n;
        scanf("%d",&n);
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                field[i][j] = 0;
            }
        }
        for(int k=0;k<n;k++){
            int c,d,x,y;
            scanf("%d%d%d%d",&c,&d,&x,&y);
            x--;y--;
            int tate=2,yoko=4;
            if(d) swap(tate,yoko);
            for(int i=y;i<y+tate;i++){
                for(int j=x;j<x+yoko;j++){
                    field[i][j] = c;
                }
            }
        }
        /*
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                printf("%2d",field[i][j]);
            }
            printf("\n");
        }
        */


        if(dfs(ys,xs))cout << "OK" << endl;
        else cout << "NG" << endl;
    }

    return 0;
}

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

int F[102][102];
int xg,yg;
int flag = 0;

void DFS(int Y,int X,int c){
  if(F[Y][X]!=c){
    return 0;
  }
  if(Y == xg && X == yg){
    flag = 1;
  }

  F[Y][X] = 0;
  DFS(Y-1,X  ,c);
  //DFS(Y-1,X+1,c);
  DFS(Y  ,X+1,c);
  //DFS(Y+1,X+1,c);
  DFS(Y+1,X  ,c);
  //DFS(Y+1,X-1,c);
  DFS(Y  ,X-1,c);
  //DFS(Y-1,X-1,c);
}


int main(){
  int w,h,xs,ys,n;
  cin >> w >> h >> xs >> ys >> xg >> yg >> n;
  for(int i=0;i<n;i++){
    int c,d,x,y;
    cin >> c >> d >> x >> y;
    if(d == 0){
      for(int j=0;j<4;j++){
        F[x+j][y] = c;
        F[x+j][y+1] = c;
      }
    } else {
      for(int j=0;j<4;j++){
        F[x][y+j] = c;
        F[x+1][y+j] = c;
      }
    }
  }

  DFS(xs,ys,F[xs][ys]);
  if(flag == 1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }

}

C++: #include <bits/stdc++.h>

using namespace std;

bool dfs(int xs,int ys,int xg,int yg,vector<vector<bool> >& canGo){
canGo[xs][ys]=false;
if(xs==xg&&ys==yg)return true;
if(canGo[xs+1][ys]){if(dfs(xs+1,ys,xg,yg,canGo))return true;}
if(canGo[xs-1][ys]){if(dfs(xs-1,ys,xg,yg,canGo))return true;}
if(canGo[xs][ys+1]){if(dfs(xs,ys+1,xg,yg,canGo))return true;}
if(canGo[xs][ys-1]){if(dfs(xs,ys-1,xg,yg,canGo))return true;}
return false;
}
int main(void){
int w,h,xs,ys,xg,yg,n;
bool ans;
vector<vector<bool> > blockmap;
while(true){
cin>>w>>h;
if(w==0&&h==0)break;
cin>>xs>>ys>>xg>>yg>>n;
blockmap=vector<vector<bool> >(w+2,vector<bool>(h+2,false));
for(int i=0;i<n;i++){
    int c,d,x,y;
    cin>>c>>d>>x>>y;
    if(c==2){
        blockmap[x+1][y+1]=true;
        blockmap[x+2][y+1]=true;
        blockmap[x+1][y+2]=true;
        blockmap[x+2][y+2]=true;
        if(d==0){
            blockmap[x+3][y+1]=true;
            blockmap[x+3][y+2]=true;
            blockmap[x+4][y+1]=true;
            blockmap[x+4][y+2]=true;
        }
        else {
            blockmap[x+1][y+2]=true;
            blockmap[x+2][y+3]=true;
            blockmap[x+1][y+4]=true;
            blockmap[x+2][y+4]=true;
        }
    }
}
ans=dfs(xs+1,ys+1,xg+1,yg+1,blockmap);
if(ans)cout<<"OK"<<endl;
else cout<<"NG"<<endl;
}
return 0;
}