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;
int w,h,xs,ys,n,xg,yg,c,d,x,y,area[105][105],c_area[105][105];
int x_p[4]={-1,0,1,0},y_p[4]={0,-1,0,1};

bool flag=false;
void solve(int x,int y,int c);

int main(){
    while(1){
        cin >> w >> h;
        if(w==0&&h==0)break;
        cin >> xs >> ys >> xg >> yg >> n;
        for(int i=0;i<n;i++){
            cin >> c >> d >> x >> y;
            if(d==0){
            for(int j=y;j<y+2;j++){
                for(int k=x;k<x+4;k++){
                    area[k][j]=c;
                }
            }
            }else{
            for(int j=y;j<y+4;j++){
                for(int k=x;k<x+2;k++){
                    area[k][j]=c;
                    }
                }
            }
        }
        if(area[xs][ys]!=area[xg][yg]);
        else {
        solve(xs,ys,area[xs][ys]);
        }
        if(flag==true)cout << "OK" << endl;
        else cout << "NG" << endl;
        flag=false;
        fill(area[0],area[104],0);
    }

return 0;
}

void solve(int x,int y,int c){

    if(x==xg&&y==yg){
        flag=true;
    return;
    }else{
        for(int i=0;i<4;i++){
        if(area[x+x_p[i]][y+y_p[i]]==c){
                //c_area[x][y]=area[x][y];
                area[x][y]=0;
                solve(x+x_p[i],y+y_p[i],c);
                //area[x][y]=c_area[x][y];
            }
        }
    }
}

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



typedef vector<vector<int> > Matrix;
int w,h,xs,ys,xg,yg,n,color;
string res = "NG";
Matrix board(101, vector<int>(101,0));

void write(Matrix &board,int c, int d, int x, int y){
  int width,length;
  if(d == 0){ width = 4; length =2; }
  if(d == 1){ width = 2; length =4; }
  for(int i=0; i<width; ++i){
    for(int j=0; j<length; ++j)
      board[x+i][y+j]=c;
  }
}
void func(Matrix &board,int nx,int ny){
  if(board[nx][ny] == 0){
    res = "NG";
    return;
  }
  if( nx==xg && ny==yg){
    res = "OK";
    return;
  }
  board[nx][ny] = 0;
  if( 0<=nx-1 && color==board[nx-1][ny])
    func(board,nx-1,ny);
  if( 0<=ny-1 && color==board[nx][ny-1])
    func(board,nx,ny-1);
  if( nx+1<=w && color==board[nx+1][ny])
    func(board,nx+1,ny);
  if( ny+1<=h && color==board[nx][ny+1])
    func(board,nx,ny+1);
}


int main(void){
  int c,d,x,y;
  while(cin >> w >> h,w||h){
    if( w==0 && h==0) return 0;
    res = "NG";
    cin >> xs >> ys >> xg >> yg >> n;
    xs--; ys--; xg--; yg--;
    //    Matrix board(w, vector<int>(h,0));
    for(int i=0; i<n; ++i){
      cin >> c >> d >> x >> y;
      --x; --y;
      write(board,c,d,x,y);
    }
    color = board[xs][ys];
    func(board,xs,ys);
    cout << res << endl;
    //    board.clear();
  }
  return 0;
}

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


#define rep(i,n) for(short i = 0; i < n; i++)
#define MAX 50

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

typedef pair<short,short> P;
P S,G;
short w,h;

short color;
	queue<P> que;
	que.push(S);
bool check(short maze[MAX][MAX])
{
	

	color = maze[S.second][S.first];

	short nx,ny;
	while(que.size()){
		P p = que.front();	que.pop();

		if(p == G){
			while(que.size())
				que.pop();
			return true;
		}

		rep(i,4){
			nx = p.first + dx[i], ny = p.second + dy[i];
			
			if(nx > -1 && ny > -1 && nx < w && ny < h &&
				maze[ny][nx] == color){
					maze[ny][nx] = -1;
					que.push(P(nx,ny));
			}

		}
	}


	
	return false;
}

int main(void)
{
	short n,c,d,x,y;
	short maze[MAX][MAX];
	while(cin >> w >> h, w){
		cin >> S.first >> S.second;
		cin >> G.first >> G.second;
		S.first = S.first / 2;
		S.second= S.second/ 2;

		cin >> n;

		rep(i,n){
			cin >> c >> d >> x >> y;
			x /= 2;
			y /= 2;
			x++;
			y++;

			if(d == 0)
				maze[y][x] = maze[y][x+1] = c;
			else
				maze[y][x] = maze[y+1][x] = c;
		}
		
		if(maze[S.second][S.first] == maze[G.second][G.first] && check(maze))
			cout << "OK\n";
		else
			cout << "NG\n";

	}
	
	return 0;
}

C++: #include <iostream>
int m[101][101],w,h,r,gx,gy;
void dfs(int x,int y,int c){
	if(!(x-gx)&&!(y-gy))r=1;
	if(x>1&&m[x-1][y]==c)m[x-1][y]=0,dfs(x-1,y,c);
	if(x<w&&m[x+1][y]==c)m[x+1][y]=0,dfs(x+1,y,c);
	if(y>1&&m[x][y-1]==c)m[x][y-1]=0,dfs(x,y-1,c);
	if(y<h&&m[x][y+1]==c)m[x][y+1]=0,dfs(x,y+1,c);
	return ;
}

int main(){
	//whÍ{[hÌå«³AnÍubNÌÂ
	int n,c,d,sx,sy,bx,by;
	
	while(std::cin>>w>>h,w&&h){
		for(int y=0;y<101;y++){
			for(int x=0;x<101;x++){
				m[x][y] = 0;
			}
		}
		r=0;
		std::cin>>sx>>sy;
		std::cin>>gx>>gy;
		std::cin>>n;
		for(int i=0;i<n;i++){
			std::cin>>c>>d>>bx>>by;
			int bw,bh;
			d?bw=2,bh=4:bh=2,bw=4;
			for(int y=by;y<=by+bh;y++){
				for(int x=bx;x<=bx+bw;x++){
					m[x][y] = c;
				}
			}
		}
		if(m[sx][sy])dfs(sx,sy,m[sx][sy]),m[sx][sy] = 0;
		if(r)std::cout<<"OK"<<std::endl;
		else{std::cout<<"NG"<<std::endl;}
	}
	return 0;
}