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 <cstdio>
#include <cstring>
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
int M[100][100];
bool vst[100][100];
int w,h,xs,ys,xg,yg,n;
bool dfs(int x,int y) {
	if(x==xg&&y==yg) return true;
	vst[x][y]=true;
	for(int i=0;i<4;i++) {
		int nx=x+dx[i],ny=y+dy[i];
		if(0>nx||nx>=w||0>ny||ny>=h)continue;
		if(M[x][y]!=M[nx][ny])continue;
		if(vst[nx][ny])continue;
		if(dfs(nx,ny))return true;
	}
	return false;
}
int main() {
	while(scanf("%d %d",&w,&h),w) {
		memset(vst,0,sizeof(vst));
		memset(M,0,sizeof(M));
		scanf("%d %d",&xs,&ys);xs--;ys--;
		scanf("%d %d",&xg,&yg);xg--;yg--;
		scanf("%d",&n);
		for(int i=0;i<n;i++) {
			int c,d,x,y;
			scanf("%d %d %d %d",&c,&d,&x,&y);x--;y--;
			if(d==1) {
				for(int j=0;j<4;j++)
					for(int k=0;k<2;k++)
						M[x+k][y+j]=c;
			}else {
				for(int j=0;j<2;j++)
					for(int k=0;k<4;k++) 
						M[x+k][y+j]=c;
			}
		}
		printf("%s\n",dfs(xs,ys)?"OK":"NG");
	}
}

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[102][102],MF[102][102];
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(Y>0 && X>0){
		if(MAP[Y-1][X] == M && MF[Y-1][X] == 0){
			Block(X,Y-1); //???
			MF[Y][X-1]=0;
		}
		if(MAP[Y+1][X] == M && MF[Y+1][X] == 0){
			Block(X,Y+1); //???
			MF[Y+1][X]=0;
		}
		if(MAP[Y][X-1] == M && MF[Y][X-1] == 0){
			Block(X-1,Y); //???
			MF[Y][X-1]=0;
		}
		if(MAP[Y][X+1] == M && MF[Y][X+1] == 0){
			Block(X+1,Y); //???
			MF[Y][X-1]=0;
		}
	}
}

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

int C[102][102];

void meiro(int W,int H,int c){
  if(C[W][H]!=c){
    return;
  }

  C[W][H] = -1;

  meiro(W-1,H  ,c);
  meiro(W  ,H+1,c);
  meiro(W+1,H  ,c);
  meiro(W  ,H-1,c);
}

void print(int w,int h){
    for(int i=1;i<=w;i++){
        for(int j=1;j<=h;j++){
            cout<<C[i][j]<<' ';
        }
        cout<<endl;
    }
}

int main(){
  while(1){
    int w,h;
    cin >> w >> h;
    if(w==0 && h==0){
      break;
    }

    for(int i=0;i<102;i++){
      for(int j=0;j<102;j++){
        C[i][j] = 0;
      }
    }

    int xs,ys,xg,yg;
    cin >> xs >> ys >> xg >> yg;

    int n;
    cin >> n;

    int c,d,x,y;
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;

      if(d==0){
        for(int j=x;j<x+4;j++){
          for(int k=y;k<y+2;k++){
            C[j][k]=c;
          }
        }
      }else{
        for(int j=x;j<x+2;j++){
          for(int k=y;k<y+4;k++){
            C[j][k]=c;
          }
        }
      }
    }
    //print(w,h);
    //cout << endl;
    meiro(xs,ys,C[xs][ys]);
    //print(w,h);

    if(C[xg][yg] == -1){
      cout << "OK" << endl;
    }else{
      cout << "NG" << endl;
    }
  }

  return 0;
}

C++: #include<iostream>
#include<cstring>
#include<queue>
#include<map>
using namespace std;
int C,goal,n,x,y,xs,ys,xg,yg,mas[110][110]={{0}};
int dx[4]={0,0,1,1};
int dy[4]={0,1,0,1};
int d[110][110];
typedef pair<int,int>P;

int bfs();
int main(){

  while(1){
    goal=0;
    memset(mas,0,sizeof(mas));
    cin >> x >> y;//ボードの大きさ。 ※：x=横。y=縦。
    if(x==0 && y==0){
      break;
    }
    cin >> xs >> ys;//スタート地点。
    cin >> xg >> yg;//ゴール地点。
    cin >> n;//ブロックの数。
    
    //色染め。
    int color,dire,xx,yy;
    for(int t=0;t<n;t++){
      cin >> color >> dire >> xx >> yy;

      //横長。
      if(dire==0){
	for(int i=0;i<2;i++){
	  for(int j=0;j<4;j++){
	    mas[yy+i][xx+j]=color;
	  }
	}
      }
      
      //縦長。
      else{
	for(int i=0;i<4;i++){
	  for(int j=0;j<2;j++){
	    mas[yy+i][xx+j]=color;
	  }
	}
      }
      
    }
    
    //通る色　摘出。
    C=mas[ys][xs];
    //cout << "color:" << C << endl;
    
    if(C!=0){

      bfs();

    
      if(goal==1){
	cout << "OK" << endl;
      }
      else{
	cout << "NG" << endl;
      }
    }
    else{
      cout << "NG" << endl;
    }
  }
}

int bfs(){
  queue<P>que;
  memset(d,-1,sizeof(d));
  que.push(P(ys,xs));
  d[ys][xs]=0;
  while(!que.empty()){
    P p=que.front();
    que.pop();
    if(p.first==yg && p.second==xg){
      goal=1;
      break;
    }
    for(int i=0;i<4;i++){
      int ny=p.first+dy[i];
      int nx=p.second+dx[i];
      if(mas[ny][nx]==C && ny>=1 && ny<=y && nx>=1 && nx<=x && d[ny][nx]==-1){
	que.push(P(ny,nx));
      }
    }
  }
  return (0);
}