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 <cstdio>
#include <string>
#include <sstream>
#include <algorithm>
#include <math.h>
#include <map>
#include <iomanip>
#include <vector>

using namespace std;



int w, h, xs, ys, xg, yg, n, c, d, x, y;
int board[100][100];	//添字は行、列の順
int dirx[] = {-1, 0, 0, 1};
int diry[] = {0, -1, 1, 0};
//xs,ysから接する同じ色のところを100に置き換えていく
void dfs(int x, int y)
{
	board[y][x] = 6;
	
	for (int i=0; i<4; i++)
	{
		int nx, ny;
		
		nx = x + dirx[i];
		ny = y + diry[i];
		
		if (0<=nx && nx<w && 0<=ny && ny<h && board[ny][nx]==c)
		{
			dfs(nx, ny);
		}
	}
}


int main()
{
	while (cin >> w >> h)
	{
		if (w == 0 && h == 0) break;
		
		cin >> xs >> ys >> xg >> yg >> n;
		
		//board初期化
		for (int i=0; i<h; i++)
		{
			for (int j=0; j<w; j++)
			{
				board[i][j] = 0;
			}
		}
		
		for (int i=0; i<n; i++)
		{
			cin >> c >> d >> x >> y;
			if (d == 0)
			{
				//横向き
				board[y-1][x-1] = board[y-1][x] = board[y-1][x+1] = board[y-1][x+2] = c;
				board[y][x-1] = board[y][x] = board[y][x+1] = board[y][x+2] = c;
			} else {
				//縦向き
				board[y-1][x-1] = board[y][x-1] = board[y+1][x-1] = board[y+2][x-1] = c;
				board[y-1][x] = board[y][x] = board[y+1][x] = board[y+2][x] = c;
			}
		}
		
		dfs(xs-1, ys-1);
		if (board[yg-1][xg-1] == 6)
		{
			cout << "OK" << endl;
		} else {
			cout << "NG" << endl;
		}
		
		/*
		//テスト出力
		for (int i=0; i<h; i++)
		{
			for (int j=0; j<w; j++)
			{
				cout << board[i][j];
			}
			cout << endl;
		}
		*/
	}
	
	return 0;
}

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

int w, h, xs, ys, xg, yg, n;
int board[110][110];
bool used[110][110];

int dx[4] = {0, -1, 1, 0};
int dy[4] = {-1, 0, 0, 1};

bool valid(int x, int y) {
    return 0 < x && x <= w && 0 < y && y <= h;
}

bool dfs(int x, int y) {
    if (x == xg && y == yg) return true;
    used[y][x] = true;
    for (int i=0; i<4; ++i) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        if (valid(nx, ny) && ! used[ny][nx] && board[ny][nx] == board[y][x] && dfs(nx, ny)) {
            return true;
        }
    }
    return false;
}

int main() {
    while (cin >> w >> h, (w || h)) {
        cin >> xs >> ys >> xg >> yg >> n;
        int c, d, x, y;
        for (int i=0; i<n; ++i) {
            cin >> c >> d >> x >> y;
            for (int j=0; j<2; ++j) {
                for (int k=0; k<4; ++k) {
                    if (d == 0) {
                        board[y + j][x + k] = c;
                    } else {
                        board[y + k][x + j] = c;
                    }
                }
            }
        }
        memset(used, false, sizeof used);
        cout << (dfs(xs, ys) ? "OK" : "NG") << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<queue>
#include<vector>
#include<list>

typedef struct block
{
	int x;
	int y;
	int h;
	int w;
	int color;
}block;

block blocks[1280];

std::queue<int> que;
std::list<int> adjacive[1280];

void makelist(int n);
bool BFS(int start,int goal);

int main()
{
	int n,w,h,xs,ys,xg,yg,start,goal;
	while(1)
	{
		while(!que.empty()){que.pop();}
		start=0;
		goal=0;
		std::cin>>w>>h;
		if(w==0&&h==0)break;
		std::cin>>xs>>ys>>xg>>yg>>n;
		for(int i=0;i<n;i++)
		{
			int c,d,x,y;
			std::cin>>c>>d>>x>>y;
			blocks[i].color=c;
			blocks[i].x=x;
			blocks[i].y=y;
			if(d==0)
			{
				blocks[i].h=2;
				blocks[i].w=4;
			}
			else
			{
				blocks[i].h=4;
				blocks[i].w=2;
			}
			if(blocks[i].x<=xs&&blocks[i].x+blocks[i].w>=xs&&blocks[i].y<=ys&&blocks[i].y+blocks[i].h>=ys)
			{
				start=i;
			}
			else if(blocks[i].x<=xg&&blocks[i].x+blocks[i].w>=xg&&blocks[i].y<=yg&&blocks[i].y+blocks[i].h>=yg)
			{
				goal=i;
			}
		}
		makelist(n);
		if(BFS(start,goal))
		{
			std::cout<<"OK"<<std::endl;
		}
		else
		{
			std::cout<<"NG"<<std::endl;
		}
	}
	return 0;
}

void makelist(int n)
{
#define x1 blocks[i].x
#define y1 blocks[i].y
#define h1 blocks[i].h
#define w1 blocks[i].w
#define x2 blocks[j].x
#define y2 blocks[j].y
#define h2 blocks[j].h
#define w2 blocks[j].w

	for(int i=0;i<n;i++)
	{
		adjacive[i].clear();
		for(int j=0;j<n;j++)
		{
			if(blocks[i].color==blocks[j].color)
			{
				if((x1==x2+w2&&y1<=y2+h2&&y1+h1>=y2)||(x2==x1+w1&&y1<=y2+h2&&y1+h1>=y2)||(y1==y2+h2&&x1<=x2+w2&&x1+w1>=x2)||(y2==y1+h1&&x1<=x2+w2&&x2<=x1+w1))
				{
					adjacive[i].push_back(j);
				}
			}
		}
	}
}

bool BFS(int start,int goal)
{
	bool visited[1280]={false};
	int survey;
	que.push(start);
	
	while(!que.empty())
	{
		survey=que.front();
		que.pop();
		for(std::list<int>::iterator it=adjacive[survey].begin();it!=adjacive[survey].end();it++)
		{
			if(visited[*it]==false)
			{
				que.push(*it);
				visited[*it]=true;
			}
		}
		if(survey==goal)
		{
			return true;
		}
	}
	return false;
}