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 <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;

int w,h,sx,sy,gx,gy,d[100][100],dx[4]={1,0,-1,0},dy[4]={0,1,0,-1},C;
int field[101][101];
const int INF=9999999;
typedef pair<int,int> P;

void bfs(){
	queue<P> que;
	for(int i=0;i<=h;i++)for(int j=0;j<=w;j++)d[i][j]=INF;
	que.push(P(sy,sx));
	d[sy][sx]=0;
	while(!que.empty()){
		P p=que.front(); que.pop();
		if(p.first==gy&&p.second==gx)break;
		for(int i=0;i<4;i++){
			int ny=p.first+dx[i],nx=p.second+dy[i];
			if(1<=ny&&ny<=h&&1<=nx&&nx<=w&&field[ny][nx]==C&&d[ny][nx]==INF){
			que.push(P(ny,nx));
			d[ny][nx]=d[p.first][p.second]+1;
			}
		}
	}
	if(d[gy][gx]==INF)cout<<"NG"<<endl;
	else cout<<"OK"<<endl;
}

int main() {
	while(cin>>h>>w){
		if(!h)return 0;
		int n,c,di,x,y;
		cin>>sx>>sy>>gx>>gy>>n;
		for(int i=1;i<=h;i++)for(int j=1;j<=w;j++)field[i][j]=0;
		for(int i=0;i<n;i++){
			cin>>c>>di>>x>>y;
			for(int j=y;j<=y+2+di*2;j++)for(int k=x;k<=x+2+!di*2;k++)field[j][k]=c;
		}
		C=field[1][1];
		bfs();
	}
}

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int fie[101][101],ans,gol[101][101],st[101][101],col,muki,bx,by;
int bex[4]={0,1,0,-1},bey[4]={1,0,-1,0},cou,a,b;
    int sx,sy,gx,gy,n;
int func(int y,int x){
    if(fie[sy][sx]==-1)return 0;
    if(y<1||x<1||y>b||x>a)return 0;
    if(fie[y][x]==ans){
        fie[y][x]=0;
        for(int i=0;i<4;i++){
            func(y+bey[i],x+bex[i]);
        }
    }
    return 0;
}
int main(){
    for(;;){
        cin>>a>>b;
        if(a==0&&b==0)break;
        fill(fie[0],fie[0]+101*101,-1);
        cin>>sx>>sy>>gx>>gy;
        cin>>n;
        for(int i=0;i<n;i++){
            cin>>col>>muki>>bx>>by;
            if(muki==0){
                for(int i=0;i<=1;i++){
                    for(int j=0;j<=3;j++){
                        fie[by+i][bx+j]=col;
                    }
                }
            }
            if(muki==1){
                for(int i=0;i<=3;i++){
                    for(int j=0;j<=1;j++){
                        fie[by+i][bx+j]=col;
                    }
                }
            }
        }
        ans=fie[sy][sx];
        if(fie[sy][sx]!=0){
            func(sy,sx);
        }
        /*for(int i=1;i<=a;i++){
            for(int j=1;j<=b;j++){
                cout<<fie[i][j];
            }
            cout<<endl;
        }*/
        if(!fie[gy][gx])cout<<"OK"<<endl;
        else cout<<"NG"<<endl;
        cou=0;
        /*for(int i=1;i<=a;i++){
            for(int j=1;j<=b;j++){
                cout<<fie[i][j];
            }
            cout<<endl;
        }*/
    }
return 0;
}
/*6 5
1 1
5 5
3
2 0 1 1
2 0 2 3
2 0 2 5
*/

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

int a=0;
int F[102][102];
void DFS(int Xs,int Ys,int c,int Xg,int Yg){
  if(F[Xs][Ys]!=c){
    return;
  }else if(Xs==Xg&&Ys==Yg){
    a=1;
    return;
  }
 F[Xs][Ys]=0;
 DFS(Xs-1,Ys,c,Xg,Yg);
 DFS(Xs,Ys-1,c,Xg,Yg);
 DFS(Xs+1,Ys,c,Xg,Yg);
 DFS(Xs,Ys+1,c,Xg,Yg);
}

int main(){
  while(1){
    a=0;
   int w,h,xs,ys,xg,yg,n,C;
   cin>>w>>h;
   if(w==0&&h==0){
     break;
   }
   cin>>xs>>ys>>xg>>yg>>n;
   int c[n],d[n],x[n],y[n];
   for(int i=0;i<n;i++){
     cin>>c[i]>>d[i]>>x[i]>>y[i];
     if(xs==x[i]&&ys==y[i]){
       C=c[i];
     }
      for(int j=0;j<4;j++){
        for(int k=0;k<2;k++){
          if(d[i]==0){
           F[x[i]+j][y[i]+k]=c[i];
         }else{
           F[x[i]+k][y[i]+j]=c[i];
         }
       }
     }
    }
    DFS(xs,ys,C,xg,yg);
    if(a==1){
      cout<<"OK"<<endl;
    }else{
      cout<<"NG"<<endl;
    }
  }
}

C++: #include<iostream>
using namespace std;
#define MAX_H 100
#define MAX_W 100
#define INF 1000;
int h,w;
int field[MAX_H][MAX_W+1];
int dx[4]={0,-1,0,1},dy[4]={-1,0,1,0};
void dfs(int y,int x,const int sc){
	if(y<=0 || x<=0 || y>=h || x>=w)return;
	if(field[y][x]==sc){
		field[y][x]=0;
		for(int i=0;i<4;i++)dfs(y+dy[i],x+dx[i],sc);
	}
	return;
}
int main(){
	int sx,sy,gx,gy,n;
	while(cin>>w>>h,w&&h){
		cin>>sx>>sy>>gx>>gy>>n;
		for(int i=0;i<MAX_H;i++){
			for(int j=0;j<MAX_W;j++){
					field[i][j]=INF;
				}
		}
		while(n--){
			int c,d,x,y;
			cin>>c>>d>>x>>y;
			for(int i=0;i<2;i++){
				for(int j=0;j<4;j++){
					if(d)field[y+j][x+i]=c;
					else field[y+i][x+j]=c;	
				}	
			}	
		}
		dfs(sy,sx,field[sy][sx]);		
		if(field[gy][gx])cout<<"NG"<<endl;
		else cout<<"OK"<<endl;
		
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define ANSWER(x) cout<<x<<endl
#define debug(x) cout<<#x<<": "<<x
const int BA = 1000;
const int INFTY = (1<<21);
int xg,yg,w,h,gc;
int maps[101][101];
int solve(int ys,int xs);
int main(){
  int tate[2] = {2,4},yoko[2] = {4,2};
  int xs,ys,n;
  int c[101],d[101],x[101],y[101];
  while(1){
    fill(maps[0],maps[101],0);
    cin >> w >> h;
    if(!w && !h)break;
    cin >> xs >> ys >> xg >> yg >> n;
    xs--;ys--;xg--;yg--;
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
      x[i]--;y[i]--;
    }
    for(int i=0;i<n;i++){
      for(int j=y[i];j<y[i]+tate[d[i]];j++){
	for(int k=x[i];k<x[i]+yoko[d[i]];k++){
	  if(j == ys && k == xs)gc = c[i];
	  maps[j][k] = c[i];
	}
      }
    }
    if(solve(ys,xs))cout << "OK\n";
    else cout << "NG\n";
  }
}
int solve(int ys,int xs){
  if(xs < 0 || ys < 0 || xs > w-1 || ys > h-1 || !maps[ys][xs] || maps[ys][xs] != gc){
    return 0;
  }
  else if(ys == yg && xs == xg){
    return 1;
  }
  maps[ys][xs] = 0;
  return solve(ys+1,xs) + solve(ys,xs+1)+ solve(ys-1,xs) + solve(ys,xs-1);
}