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<cfloat>
#include<cstring>
#define foreach(t,p,it) for(t::iterator it=p.begin(),it!=p.end(),++it)
#define all(p) p.begin(),p.end()
#define rep(i,n) for(int i=0;i<n;i++)
#define REP(n) rep(i,n)
using namespace std;

const int W=210,H = 210;
int block[W][H];
int ans;

int w,h,xs,ys,xg,yg,n,c,d,x,y;
void solve(int xi,int yi)
{
    if(ans == 1) return ;
    //cout << xi <<" " << yi << endl;
    if(xi==xg && yi==yg){ ans = 1; return;}
    if(block[xi][yi] == c)
    {
        block[xi][yi] = 0;
        solve(xi-1,yi);
        solve(xi,yi-1);
        solve(xi+1,yi);
        solve(xi,yi+1);
    }
    else return;
}

int main()
{
    while(cin >> w >> h )
    {
        if(w==0 && h==0) break;
        memset(block,0,sizeof(block));
        ans = 0;
        cin >> xs >> ys;
        cin >> xg >> yg;
        cin >> n;
        REP(n)
        {
            cin >> c >> d >> x >> y;
            //cout << x << ","<< y << endl;
            if(d==1) //tate
            {
                block[x][y] = c;
                block[x][y+1] =c;
                block[x][y+2] = c;
                block[x][y+3] = c;
                block[x+1][y] = c;
                block[x+1][y+1] = c;
                block[x+1][y+2] = c;
                block[x+1][y+3] = c;
            }
            else
            {
                block[x][y] = c;
                block[x+1][y] = c;
                block[x+2][y] = c;
                block[x+3][y] = c;
                block[x][y+1] = c;
                block[x+1][y+1] = c;
                block[x+2][y+1] = c;
                block[x+3][y+1] = c;
            }
        }
        c = block[xs][ys];
        if(c==0) {cout <<"NG" << endl; continue;}
        
        //cout << xs << " " << ys << " " << c << endl;
        //cout <<"input " << endl;
        solve(xs,ys);

        if(ans) cout << "OK" << endl;
        else cout << "NG" << endl;

    }

    return 0;
}

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

int n, w, h, xs, ys, xg, yg, f[105][105] = { 0 }, dx[] = { 0,1,0,-1 }, dy[] = { 1,0,-1,0 }, used[105][105] = { 0 }, color = 0;
bool flag;
void dfs(int y, int x) {
	for (int i = 0; i < 4; i++) {
		int nx = x + dx[i];
		int ny = y + dy[i];
		if (xg == nx&&yg == ny) {
			flag = true;
			return;
		}
		if (used[ny][nx]) continue;
		if (1 <= nx&&nx <= w && 1 <= ny&&ny <= h&&f[ny][nx] == color) {
			used[ny][nx] = 1;
			dfs(ny, nx);
		}
	}
	return;
}

int main() {
	while (1) {
		for (int i = 0; i < 105; i++) {
			for (int j = 0; j < 105; j++) {
				f[i][j] = 0;
				used[i][j] = 0;
			}
		}
		flag = false;
		cin >> w >> h;
		if (w == 0 && h == 0) return 0;
		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 == 0) {
				for (int j = 0; j < 2; j++) {
					for (int k = 0; k < 4; k++) {
						f[y + j][x + k] = c;
					}
				}
			}
			else {
				for (int j = 0; j < 4; j++) {
					for (int k = 0; k < 2; k++) {
						f[y + j][x + k] = c;
					}
				}
			}
		}
		used[ys][xs] = 1;
		color = f[ys][xs];
		dfs(ys, xs);
		if (color == 0) {//?????????????????????????????????
			cout << "NG" << endl; continue;
		}
		if (flag) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <sstream>
#include <cmath>
#include <queue>

using namespace std;

int w, h;

int map[200][200];

void search(int x, int y, int col){
	if(x < 0 || y < 0 || x >= w || y >= h){
		return;
	}
	if(map[x][y] != col || map[x][y] == 0){
		return;
	}
	map[x][y] = 0;
	search(x - 1, y, col);
	search(x + 1, y, col);
	search(x, y - 1, col);
	search(x, y + 1, col);
}

int main(){
	
	
	while(true){
		
		cin >> w >> h;
		if(w == 0 && h == 0){
			break;
		}
		
		int xs, ys, xg, yg;
		
		cin >> xs >> ys >> xg >> yg;
		
		int n;
		
		cin >> n;
		
		for(int i = 0; i <= w; i++){
			for(int j = 0; j <= h; j++){
				map[i][j] = 0;
			}
		}
		
		for(int loop = 0; loop < n; loop++){
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			if(d == 0){
				for(int dx = 0; dx < 4; dx++){
					for(int dy = 0; dy < 2; dy++){
						map[x + dx][y + dy] = c;
					}
				}
			}else{
				for(int dx = 0; dx < 2; dx++){
					for(int dy = 0; dy < 4; dy++){
						map[x + dx][y + dy] = c;
					}
				}
			}
		}
		
		if(map[xs][ys] == 0 || map[xg][yg] == 0){
			cout << "NG" << endl;
		}else{
			search(xs, ys, map[xs][ys]);
			if(map[xg][yg] == 0){
				cout << "OK" << endl;
			}else{
				cout << "NG" << endl;
			}
		}
		/*
		for(int y = 1; y <= h; y++){
			for(int x = 1; x <= w; x++){
				cout << map[x][y];
			}
			cout << endl;
		}
		*/
	}
	
	return 0;
}

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

int F[102][102];

void
DFS (int Y, int X, int A)
{
  if (F[Y][X] != A)
    return;

  F[Y][X] = 7;

  DFS (Y - 1, X, A);
  DFS (Y, X + 1, A);
  DFS (Y + 1, X, A);
  DFS (Y, X - 1, A);
}

int
main ()
{
  int w, h;
  int xs, ys;
  int xg, yg;
  int n;
  int c, d, x, y;

  while (true)
    {
      cin >> w >> h;
      if (w == 0 && h == 0)
	break;
      cin >> xs >> ys;
      cin >> xg >> yg;
      cin >> n;

      for (int i = 0; i < n; i++)
	{
	  cin >> c >> d >> x >> y;
	  if (d == 0)
	    {
	      for (int a = 0; a < 4; a++)
		{
		  for (int b = 0; b < 2; b++)
		    {
		      F[y + b][x + a] = c;
		    }
		}

	    }
	  else
	    {
	      for (int a = 0; a < 2; a++)
		{
		  for (int b = 0; b < 4; b++)
		    {
		      F[y + b][x + a] = c;
		    }
		}
	    }

	}


      if (F[ys][xs] == 1 || F[ys][xs] == 2 || F[ys][xs] == 3
	  || F[ys][xs] == 4 || F[ys][xs] == 5)
	{
	  DFS (ys, xs, F[ys][xs]);
	}

      if (F[yg][xg] == F[ys][xs])
	{
	  cout << "OK" << endl;
	}
      else
	{
	  cout << "NG" << endl;
	}

    /*for (int y = 0; y < h; y++)
	{
	  for (int x = 0; x < w; x++)
	    {
	      cout << F[y][x];
	    }
         cout << endl;
	}*/

    }

  return 0;
}