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>
using namespace std;
#define MAX_W 100
#define MAX_H 100

int board[MAX_H + 1][MAX_W + 1];
bool ans = false;

void swapAB(int a[], int b[]);
void resetBoard();
void setBoard(int c, int d, int x, int y);
void loop(int xn, int yn, int xg, int yg, int c);
void disp(int w, int h);

int main(){
    int w, h;
    while(cin >>w >>h){
        if(w == 0 && h == 0) break;
        int xs, ys, xg, yg, n;
        resetBoard();
        ans = false;
        cin >>xs >>ys >>xg >>yg >>n;
        for(int i = 0; i < n; i++){
            int c, d, x, y;
            cin >>c >>d >>x >>y;
            setBoard(c, d, x, y);
        }
//        disp(w, h);
        if(board[ys][xs] == 0){
            cout <<"NG" <<endl;
        } else{
            loop(xs, ys, xg, yg, board[ys + 1][xs + 1]);
            if(ans) cout <<"OK" <<endl;
            else cout <<"NG" <<endl;
        }
    }
    return 0;
}   

void swapAB(int a[], int b[]){
    for(int i = 0; i < 8; i++){
        int tmp = a[i];
        a[i] = b[i];
        b[i] = tmp;
    }
}

void resetBoard(){
    for(int i = 0; i <= MAX_H; i++){
        for(int j = 0; j <= MAX_W; j++){
            board[i][j] = 0;
        }
    }
}

void setBoard(int c, int d, int x, int y){
    int xm[] = {0, 1, 2, 3, 0, 1, 2, 3}, ym[] = {0, 0, 0, 0, 1, 1, 1, 1};
    if(d == 1) swapAB(xm, ym);
    for(int i = 0; i < sizeof(xm) / sizeof(xm[0]); i++){
        int tmpx = x + xm[i], tmpy = y + ym[i];
        if(tmpx > 0 || tmpy > 0 || tmpx <= MAX_W || tmpy <= MAX_H){
            board[tmpy][tmpx] = c;
        }
    }
}
void loop(int xn, int yn, int xg, int yg, int c){
    if(xn == xg && yn == yg){
        ans = true;
    } else{
        board[yn][xn] = 0;
        int xm[] = {0, 1, 0, -1}, ym[] = {-1, 0, 1, 0};
        for(int i = 0; i < sizeof(xm) / sizeof(xm[0]); i++){
            int tmpx = xn + xm[i], tmpy = yn + ym[i];
            //            cout <<"tmpx = " <<tmpx <<", tmpy = " <<tmpy <<endl;
            if(tmpx > 0 && tmpy > 0 && tmpx <= MAX_W && tmpy <= MAX_H && board[tmpy][tmpx] == c){
                loop(tmpx, tmpy, xg, yg, c);
            }
        }
    }
}

void disp(int w, int h){
    for(int i = 0; i <= h; i++){
        for(int j = 0; j <= w; j++){
            cout <<board[i][j];
        }
        cout <<endl;
    }
}

//0, 00:50:41

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);
}

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;
    int cbase;
    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]=cbase;
          }
        }
      }
    }
    meiro(xs,ys,C[xs][ys]);

    if(C[xg][yg] == -1){
      cout << "OK" << endl;
    }
    if(C[xg][yg] != -1 || C[xs][ys] == 0){
      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;
      if(dire==0){
	for(int i=0;i<2;i++){
	  for(int j=0;j<4;j++){
	    mas[yy+i][xx+j]=color;
	  }
	}
      }
      
      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[1][1];
    
    bfs();
    
    if(goal==1){
      cout << "OK" << endl;
    }
    else{
      cout << "NO" << 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));
	d[ny][nx]=0;
      }
    }
  }
  return (0);
}

C++: #include <iostream>
using namespace std;
int F[102][102];

void DFScolor(int X,int Y,int color,int Xg,int Yg){

	if(F[X][Y]!=color)
		return;
	
	F[X][Y]=0;
	DFScolor(X-1,Y,color,Xg,Yg);
	DFScolor(X,Y+1,color,Xg,Yg);
	DFScolor(X+1,Y,color,Xg,Yg);
	DFScolor(X,Y-1,color,Xg,Yg);
	
}


int main(){
while(1){
	int H,W,xg,yg,xs,ys,n,count=0;
	cin>>H;
	if(H==0)
		count++;
	cin>>W;
	if(W==0)
		count++;
	if(count==2)
		return 0;
	cin>>xs>>ys;
	cin>>xg>>yg;	
	cin>>n;
	int c,d,x,y;
	int xb[n],yb[n],colo[n];
	for(int i=0;i<n;i++){
		
		cin>>c>>d>>x>>y;
		colo[i]=c;
		xb[i]=x;
		yb[i]=y;
		if(d==0){
			for(int o=y;o<y+2;o++){
				for(int j=x;j<x+4;j++){
					F[j][o]=c;
				}
			}
		}
		else if(d==1){
			for(int o=y;o<y+4;o++){
				for(int j=x;j<x+2;j++){
					F[j][o]=c;
				}
			}
		}
		
	}
	
	for(int i=0;i<n;i++){
		if(xb[i]==xs&&yb[i]==ys){
			DFScolor(xb[i],yb[i],colo[i],xg,yg);
			if(F[xg][yg]==0)
				cout<<"OK"<<endl;
			if(F[xg][yg]!=0)
				cout<<"NG"<<endl;
			break;
		}
	}
	
	
}
	return 0;
}