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>
using namespace std;
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <algorithm>
#include <functional> //sort(A,A.end(),greater<int>());???????????????
#include <queue>
#include <stack>
#include <vector>

#define INF 10 << 10
#define MP make_pair

int map[124][124];
bool map_flg[124][124];
int x_move[] = { 0,0,1,-1 };
int y_move[] = { -1,1,0,0 };

int main() {
	int w, h;

	while (cin >> w >> h && w != 0 && h != 0) {
		memset(map, 0, sizeof(map));
		memset(map_flg, true, sizeof(map_flg));
		int xs, ys;
		int xg, yg;
		int n;

		cin >> xs >> ys >> xg >> yg >> n;

		for (int i = 1; i <= n; ++i) {
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			int x_, y_;
			if (d == 0) {
				x_ = 4;
				y_ = 2;
			}
			else {
				x_ = 2;
				y_ = 4;
			}
			for (int j = y; j < y + y_; ++j) {
				for (int j2 = x; j2 < x + x_; ++j2) {
					map[j][j2] = c;
				}
			}
		}

		if (map[ys][xs] != map[yg][xg]) {
			cout << "NG" << endl;
			continue;
		}

		stack<pair<int, int> > st;
		st.push(MP(xs, ys));
		int m_c = map[ys][xs];
		bool flg = false;
		while (!st.empty()) {
			int x = st.top().first, y = st.top().second;
			st.pop();
			map_flg[y][x] = false;
			for (int i = 0; i < 4; ++i) {
				int x_ = x + x_move[i], y_ = y + y_move[i];
				if (map[y_][x_] == m_c && map_flg[y_][x_]) {
					if (y_ == yg && x_ == xg) {
						flg = true;
						break;
					}
					st.push(MP(x_, y_));
				}
			}
			if (flg) { break; }
		}

		if (flg) { cout << "OK" << endl; }
		else { cout << "NG" << 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;
	}

    }

  return 0;
}

C++: #include <iostream>
using namespace std;
  
int F[105][105];
int xg,yg,w,h;
  
  
void DFS(int Y,int X,int c){
  if(Y < 1 || X < 1)
    //return;
  if(F[Y][X] != c || Y > w || X > h){
    return;
  }
  
  F[Y][X] = -1;
  DFS(Y+1,X  ,c);
  DFS(Y-1  ,X,c);
  DFS(Y,X+1  ,c);
  DFS(Y  ,X-1,c);
}
  
  
int main(){
  int xs,ys,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;
for(int i=0; i<105; i++){
      for(int j=0; j<105; j++){
        F[i][j] = 10;
      }
    }
      
    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<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(F[xg][yg] == -1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
}

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); //???
}