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;

char F[101][101];

int DFS_W(int Y,int X,int Xg,int Yg,int c){
  if(F[Y][X]!='w'){
    return c;
  }
  F[Y][X]='.';
  DFS_W(Y-1,X  ,Xg,Yg,c);
  DFS_W(Y  ,X+1,Xg,Yg,c);
  DFS_W(Y+1,X  ,Xg,Yg,c);
  DFS_W(Y  ,X-1,Xg,Yg,c);
  if(Y==Xg&&X==Yg){
    c++;
  }
}
int DFS_Y(int Y,int X,int Xg,int Yg,int c){
  if(F[Y][X]!='y'){
    return c;
  }
  F[Y][X]='.';
  DFS_Y(Y-1,X  ,Xg,Yg,c);
  DFS_Y(Y  ,X+1,Xg,Yg,c);
  DFS_Y(Y+1,X  ,Xg,Yg,c);
  DFS_Y(Y  ,X-1,Xg,Yg,c);
  if(Y==Xg&&X==Yg){
    c++;
  }
}
int DFS_G(int Y,int X,int Xg,int Yg,int c){
  if(F[Y][X]!='g'){
    return c;
  }
  F[Y][X]='.';
  DFS_G(Y-1,X  ,Xg,Yg,c);
  DFS_G(Y  ,X+1,Xg,Yg,c);
  DFS_G(Y+1,X  ,Xg,Yg,c);
  DFS_G(Y  ,X-1,Xg,Yg,c);
  if(Y==Xg,X==Yg){
    c++;
  }
}
int DFS_B(int Y,int X,int Xg,int Yg,int c){
  if(F[Y][X]!='b'){
    return c;
  }
  F[Y][X]='.';
  DFS_B(Y-1,X  ,Xg,Yg,c);
  DFS_B(Y  ,X+1,Xg,Yg,c);
  DFS_B(Y+1,X  ,Xg,Yg,c);
  DFS_B(Y  ,X-1,Xg,Yg,c);
  if(Y==Xg,X==Yg){
    c++;
  }
}
  int DFS_R(int Y,int X,int Xg,int Yg,int c){
  if(F[Y][X]!='r'){
    return c;
  }
  F[Y][X]='.';
  DFS_R(Y-1,X  ,Xg,Yg,c);
  DFS_R(Y  ,X+1,Xg,Yg,c);
  DFS_R(Y+1,X  ,Xg,Yg,c);
  DFS_R(Y  ,X-1,Xg,Yg,c);
  if(Y==Xg,X==Yg){
    c++;
  }
}

int main(){
  int c[5];
  int d[1];
  int w;
  int h;
  int xs;
  int ys;
  int xg;
  int yg;
  int n;
  int x[n];
  int y[n];
  cin>>w>>h;
  while(w!=0){
    int a=0;
    int b=0;
    cin>>xs>>ys;
    cin>>xg>>yg;
    cin>>n;
    for(int i=0;i<n;i++){
      cin>>c[i]>>d[i]>>x[i]>>y[i];
        int a=0;
        int b=0;
      if(d[i]==0){
        if(c[i]==1){
          for(int z=0;z<4;z++){
            F[y[i]][x[i]+z] ='w';
            F[y[i]+1][x[i]+z] ='w';
          }
        }else if(c[i]==2){
          for(int z=0;z<4;z++){
            F[y[i]][x[i]+z] ='y';
            F[y[i]+1][x[i]+z] ='y';
          }
        }else if(c[i]==3){
          for(int z=0;z<4;z++){
            F[y[i]][x[i]+z] ='g';
            F[y[i]+1][x[i]+z] ='g';
          }
        }else if(c[i]==4){
          for(int z=0;z<4;z++){
            F[y[i]][x[i]+z] ='b';
            F[y[i]+1][x[i]+z] ='b';
          }
        }else if(c[i]==5){
          for(int z=0;z<4;z++){
            F[y[i]][x[i]+z] ='r';
            F[y[i]+1][x[i]+z] ='r';
          }
        }
      }else if(d[i]==1){
        if(c[i]==1){
          for(int z=0;z<4;z++){
            F[y[i]+z][x[i]] ='w';
            F[y[i]+z][x[i]+1] ='w';
          }
        }else if(c[i]==2){
          for(int z=0;z<4;z++){
            F[y[i]+z][x[i]] ='y';
            F[y[i]+z][x[i]+1] ='y';
          }
        }else if(c[i]==3){
          for(int z=0;z<4;z++){
            F[y[i]+z][x[i]] ='g';
            F[y[i]+z][x[i]+1] ='g';
          }
        }else if(c[i]==4){
          for(int z=0;z<4;z++){
            F[y[i]+z][x[i]] ='b';
            F[y[i]+z][x[i]+1] ='b';
          }
        }else if(c[i]==5){
          for(int z=0;z<4;z++){
            F[y[i]+z][x[i]] ='r';
            F[y[i]+z][x[i]+1] ='r';
          }
        }
      }
    }
    int cnt=0;
    if(F[ys][xs]=='w'){
      cnt=DFS_W(ys,xs,xg,yg,cnt);
    }else if(F[ys][xs]=='y'){
      cnt=DFS_Y(ys,xs,xg,yg,cnt);
    }else if(F[ys][xs]=='g'){
      cnt=DFS_G(ys,xs,xg,yg,cnt);
    }else if(F[ys][xs]=='b'){
      cnt=DFS_B(ys,xs,xg,yg,cnt);
    }else if(F[ys][xs]=='r'){
      cnt=DFS_R(ys,xs,xg,yg,cnt);
    }
    if(cnt==0){
      cout<<"NG"<<endl;
    }else if(cnt==1){
      cout<<"OK"<<endl;
    }
    cin>>w>>h;
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define FFOR(i,a,b) for(int i=(a);i<=(b);i++)
#define REP(i,b) FOR(i,0,b)
#define RREP(i,b) FFOR(i,1,b)
#define PB push_back
#define F first
#define S second
#define BE(c) c.begin(),c.end()
using namespace std;
typedef long long LL;
typedef LL ut;
typedef long double ld;
typedef pair<ut,ut> pr;
typedef vector<pr> Vpr;
typedef vector<ut> VI;
typedef pair<ut,pr> ppr;
typedef priority_queue<pr,Vpr, greater<pr> > PQ;
const int SIZE=5+3*1e+4;
const ut INF=1<<30;
const ld eps=1e-6;
const LL p=7+1e+9;

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

int W, H;
int xs, ys, xg, yg;
int N, C;
int maze[128][128];
bool check[128][128];

int dfs(int x, int y){
	if(x == xg && y == yg)
		return 1;
	
	int res = 0;
	REP(i,4){
		int nx = x + dx[i];
		int ny = y + dy[i];
		if(nx > 0 && nx <= W && ny > 0 && ny <= H && !check[ny][nx] && maze[ny][nx] == C){
			check[ny][nx] = true;
			res |= dfs(nx, ny);
		}
	}
	return res;
}

int main(){
	while(cin >> W >> H && (W || H)){
		memset(maze, 0, sizeof(maze));
		memset(check, 0, sizeof(check));
		cin >> xs >> ys >> xg >> yg >> N;
		int c, d, x, y;
		REP(i,N){
			cin >> c >> d >> x >> y;
			if(d == 0){
				REP(j,2)
					REP(k,4)
						maze[y + j][x + k] = c;
			}
			else{
				REP(j,4)
					REP(k,2)
						maze[y + j][x + k] = c;
			}
		}
		C = maze[yg][xg];
		if(C == 0 || maze[ys][xs] == 0){
			cout << "NG" << endl;
			continue;
		}
		check[ys][xs] = true;
		int ans = dfs(xs, ys);
		if(ans){
			cout << "OK" << endl;
		}
		else{
			cout << "NG" << endl;
		}
	}
}