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<string>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<complex>
#include<cmath>
#include<algorithm>
#include<map>
#include<vector>
#include<sstream>
#include<iostream>
#include<queue>
using namespace std;
const int dx[] = {1,0,-1,0},dy[] = {0,1,0,-1};
struct point{
    int x,y;
    point(){}
    point(int a, int b){x = a;y = b;}
};
int main(void){

    int w,h;
    while(cin>>w>>h,w){
        int xs,ys,xg,yg,n;
        cin>>xs>>ys>>xg>>yg>>n;
        int field[100][100] = {{0}};
        for(int i = 0;i < n;i++){
            int c,d,x,y;
            int dw = 4,dh = 2;
            cin>>c>>d>>x>>y;
            if(d)swap(dw,dh);
            for(int di = y;di < dh + y && di < h; di++){
                for(int dj = x;dj < dw + x && dj < w;dj++){
                    field[di][dj] = c;
                }
            }
        }
        int C = field[xs][ys];
        bool vis[100][100] = {{false}};
        queue<point> Q;
        Q.push(point(xs,ys));
        if(field[xg][yg] != C)cout<<"NG"<<endl;
        else {
            while(!Q.empty()){
                point P = Q.front();
                Q.pop();
                for(int i = 0;i < 4;i++){
                    point p = point(P.x + dx[i],P.y + dy[i]);
                    if(0 <= p.x && p.x < w && 0 <= p.y && p.y < h){
                        if(!vis[p.x][p.y]&&field[p.x][p.y] == C){

                            vis[p.x][p.y] = true;
                            Q.push(p);
                        }
                    }
                }
            }
        }
        if(vis[xg][yg])cout<<"OK"<<endl;
        else cout<<"NG"<<endl;
/*
        for(int i = 0;i < h;i++){
            for(int j = 0;j < w;j++){
                cout<<field[i][j]<<" ";
            }
            cout<<endl;
        }
        cout<<endl<<endl;
        for(int i = 0;i < h;i++){
            for(int j = 0;j < w;j++){
                cout<<vis[i][j]<<" ";
            }
            cout<<endl;
        }*/
    }


    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>
#include <fstream>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007
#define MOD 1000000007
#define EPS 1e-10
#define MAX_N 100100
#define MAX_M 100100

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;
typedef pair<P, char> PC;
typedef pair<int, string> PSI;

int w, h, sx, sy, gx, gy;
int n, c, d, x, y;

int table[110][110];
int dis[110][110];

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

void solve(){
	REP(i, 110)REP(j, 110)dis[i][j] = INF;
	dis[sy][sx] = 0;

	queue<P> que;
	que.push(P(sy, sx));

	while (que.size()){
		P p = que.front(); que.pop();
		int cx = p.second, cy = p.first;

		if (y == gy&&x == gx)break;

		REP(i, 4){
			int nx = cx + dx[i], ny = cy + dy[i];
			if (nx >= 0 && nx < w&&ny >= 0 && ny < h){
				if (table[ny][nx] == table[cy][cx]
					&&dis[ny][nx] == INF){
					dis[ny][nx] = dis[cy][cx] + 1;
					que.push(P(ny, nx));
				}
			}
		}
	}
}

int main(){
	while (cin >> w >> h&&w + h){
		REP(i, 110)REP(j, 110){
			table[i][j] = 0;
		}
		cin >> sx >> sy >> gx >> gy;
		sx--;
		sy--;
		gx--;
		gy--;

		cin >> n;
		REP(i, n){
			cin >> c >> d >> x >> y;
			x--;
			y--;
			if (d == 0){
				REP(i, 2){
					REP(j, 4){
						table[y + i][x + j] = c;
					}
				}
			}
			else{
				REP(i, 4){
					REP(j, 2){
						table[y + i][x + j] = c;
					}
				}
			}
		}

		solve();

		if (dis[gy][gx] != INF&&table[sy][sx] != 0 && table[gy][gx] != 0)cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}

//REP(i, h){
//	REP(j, w){
//		cout << table[i][j] << " ";
//	}
//	cout << endl;
//}
//cout << "!" << endl;
//solve();
//REP(i, h){
//	REP(j, w){
//		cout << dis[i][j] << " ";
//	}
//	cout << endl;
//}

C++: #include<stdio.h>
#include<string.h>
int gx,gy,m[128][128];
int F(int x,int y,int c)
{
	if(x==gx&&y==gy)
		return 1;
	if(m[y][x]!=c)
		return 0;
	m[y][x]=-c;
	int d[]={0,1,0,-1,0},i,f;
	for(i=f=0;i<4;++i)
		f=f||F(x+d[i],y+d[i+1],c);
	return f;
}
int main()
{
	int w,h,sx,sy,x,y,n,c,d,i,j;
	while(scanf("%d%d",&w,&h),w)
	{
		memset(m,0,sizeof(m));
		scanf("%d%d%d%d%d",&sx,&sy,&gx,&gy,&n);
		while(n--)
		{
			scanf("%d%d%d%d",&c,&d,&x,&y);
			for(i=0;i<2;++i)for(j=0;j<4;++j)
				if(d) m[y+j][x+i]=c;
				else m[y+i][x+j]=c;
		}
		if(m[sy][sx]&&F(sx,sy,m[sy][sx]))puts("YES");
		else puts("NO");
	}
	return 0;
}