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<algorithm>
#include<cstring>

using namespace std;

typedef pair<int,int> P;
const int MAX = 120;

int maze[MAX][MAX];
bool come[MAX][MAX];
P s,g;
int W,H,c;
int dx[4] = {1,0,0,-1};
int dy[4] = {0,1,-1,0};

void init(){
  memset(come,false,sizeof(come));
  memset(maze,0,sizeof(maze));
}


void input_B(){
  int n;
  cin >> n;
  while(n--){
    int c,d,x,y;
    cin >> c >> d >> x >> y;
    if(d){
      for(int i = y; i < y+4; i++)
	for(int j = x; j < x+2; j++)
	  maze[i][j] = c;
    }else{
      for(int i = y; i < y+2; i++)
	for(int j = x; j < x+4; j++)
	  maze[i][j] = c;
    }
  }
}


void solve(P p){
  
  if(come[p.second][p.first] == false){
    come[p.second][p.first] = true;
    for(int i = 0; i < 4; i++)
      if(0 < p.first+dx[i] && p.first+dx[i] <= W &&
	 0 < p.second+dy[i] && p.second+dy[i] <= H &&
	 maze[p.second+dy[i]][p.first+dx[i]] == c) solve(P(p.first+dx[i],p.second+dy[i]));
  }
}

void print(){
  for(int i = 1; i < H; i++){
    for(int j = 1; j < W; j++)// cout << come[i][j];
      cout << maze[i][j];
    cout << endl;
  }

}


int main(){
  while(cin >> W >> H && W+H){
    init();
    cin >> s.first >> s.second;
    cin >> g.first >> g.second;
    input_B();
    c = maze[s.second][s.first];
    solve(s);
    //print();
    if(come[g.second][g.first] && c) cout << "OK" << endl;
    else cout << "NG" << endl;
  }
  return 0;
}

C++: #include <iostream>

using namespace std;

int board[100][100],w,h,xg,yg;

bool f(int y,int x,int color){

	board[y][x] = -1;

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

	if(y == yg - 1 && x == xg -1) return true;

	for(i = 0;i < 4;i++){

		if(y + dy[i] > -1 && y + dy[i] < h && x + dx[i] > -1 && x + dx[i] < w){

			if(board[y+dy[i]][x+dx[i]] == color){

				if(f(y+dy[i],x+dx[i],color)) return true;

			}

		}

	}

	return false;

}

int main(){

	int xs,ys,n,i,j,k,c,d,x,y;

	while(cin >> w >> h && (w != 0 && h != 0)){

		for(j = 0;j < 100;j++){

			for(i = 0;i < 100;i++){

				board[j][i] = -1;

			}

		}

		cin >> xs >> ys;

		cin >> xg >> yg;

		cin >> n;

		for(i = 0;i < n;i++){

			cin >> c >> d >> x >> y;

			x -= 1;

			y -= 1;

			if(d == 0){

				for(j = 0;j < 2;j++){

					for(k = 0;k < 4;k++){

						board[y+j][x+k] = c;

					}

				}

			}

			else if(d == 1){

				for(j = 0;j < 2;j++){

					for(k = 0;k < 4;k++){

						board[y+k][x+j] = c;

					}

				}

			}

		}

		if(board[ys - 1][xs - 1] != -1){

			if(f(ys - 1,xs -1,board[ys - 1][xs - 1])) cout << "OK" << endl;

			else cout << "NG" << endl;

		}

		else cout << "NG" << endl;

	}

	return 0;

}

C++: #include<iostream>
using namespace std;
int w,h,xs,ys,xg,yg,n;
int map[101][101];
string ans;
void fun(int y,int x){
    if(map[y][x]==map[ys][xs]){
        map[y][x]=7;
    }
    else
        return;
    if(x<1||w<x||y<1||h<y)
        return;
    if(map[y+1][x+1]==map[yg][xg]){
        ans="OK";
        return;
    }
    fun(y,x+2);
    fun(y,x-2);
    fun(y+2,x);
    fun(y-2,x);
}
void mc(){
    int c,d,x,y;
    for(int i=0;i<n;i++){
        cin >> c >> d >> x >> y;
        if(d==0){
            for(int j=0;j<2;j++){
                for(int k=0;k<4;k++){
                    map[y+j][x+k]=c;
                }
            }
        }
        else{
            for(int j=0;j<4;j++){
                for(int k=0;k<2;k++){
                    map[y+j][x+k]=c;
                }
            }
        }
    }
}
int main(){
    while(cin >> w >> h,w){
    	ans="NG";
        cout << endl;
        cin >> xs >> ys >> xg >> yg >> n;
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                map[i][j]=0;
            }
        }
        mc();
        cout << ans << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define rep(i,s,e) for(int (i) = (s);(i) <= (e);(i)++)
#define all(x) x.begin(),x.end()

int w,h;
int sx,sy;
int gx,gy;
int n;

vector<vector<int>> field;
int de[] = {1, 0, -1, 0};

void dfs(int x ,int y, int c) {
  if(x < 1 || x > w || y < 1 || y > h || field[x][y] != c) return;
  field[x][y] = -1;
  dfs(x + 1, y, c);
  dfs(x - 1, y, c);
  dfs(x, y + 1, c);
  dfs(x, y - 1, c);
}

int main() {
  while(cin >> w >> h, w && h) {
    field.assign(101, vector<int>(101, 0));
    cin >> sx >> sy;
    cin >> gx >> gy;
    cin >> n;
    int dd[] = {4, 2};
    for(int i = 0;i < n;i++) {
      int c, d, x, y;
      cin >> c >> d >> x >> y;
      for(int xx = x; xx < x + dd[d];xx++) {
        for(int yy = y;yy < y + dd[d ^ 1];yy++) {
          field[xx][yy] = c;
        }
      }
    }
    if(field[sx][sy] == 0) {
      cout << "NG" << endl;
      continue;
    }
    dfs(sx, sy, field[sx][sy]);
    if(field[gx][gy] == -1) {
      cout << "OK" << endl;
    }
    else {
      cout << "NG" << endl;
    }
  }
}

C++: #include<iostream>

using namespace std;

int map[110][110];
int ans;
int w,h,n;

void serch(int xx,int yy,int gx,int gy,int color)
{
	map[yy][xx]=0;
	
	int nex[4]={1,0,-1,0};
	int ney[4]={0,1,0,-1};
	if(xx==gx && yy==gy)
	{
		ans=1;
		return ;
	}
	for(int i=0;i<4;i++)
	{
		if(map[yy+ney[i]][xx+nex[i]]==color)
		{
			serch(xx+nex[i],yy+ney[i],gx,gy,color);
			if(ans==1)
				return ;
		}
	}
	return ;
}

int main()
{
	int sx,sy,ex,ey;
	int i,j,k;
	int c,d,x,y;
	for(;;)
	{
		cin >> w >> h ;
		if(w==0 && h==0)
			break;
		
		ans=0;
		
		for(i=0;i<110;i++)
			for(j=0;j<110;j++)
				map[i][j]=0;
		
		cin >> sx >> sy >> ex >> ey >> n ;
		
		for(i=0;i<n;i++)
		{
			cin >> c >> d >> x >> y ;
			if(d==0)
			{
				for(j=0;j<2;j++)
					for(k=0;k<4;k++)
						map[y+j][x+k]=c;
			}
			else
			{
				for(j=0;j<4;j++)
					for(k=0;k<2;k++)
						map[y+j][x+k]=c;
			}
		}
		if(map[sy][sx]!=0)
			serch(sx,sy,ex,ey,map[sy][sx]);
		
		if(ans==1)
			cout << "OK" << endl;
		else
			cout << "NG" << endl;
	}
}