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;
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <algorithm>
#include <functional> //sort(A,A.end(),greater<int>());???????????????
#include <queue>
#include <stack>
#include <vector>

#define INF 10 << 10
#define MP make_pair

int map[124][124];
bool map_flg[124][124];
int x_move[] = { 0,0,1,-1 };
int y_move[] = { -1,1,0,0 };

int main() {
	int w, h;

	while (cin >> w >> h && w != 0 && h != 0) {
		memset(map, 0, sizeof(map));
		memset(map_flg, true, sizeof(map_flg));
		int xs, ys;
		int xg, yg;
		int n;

		cin >> xs >> ys >> xg >> yg >> n;

		for (int i = 1; i <= n; ++i) {
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			int x_, y_;
			if (d == 0) {
				x_ = 4;
				y_ = 2;
			}
			else {
				x_ = 2;
				y_ = 4;
			}
			for (int j = y; j < y + y_; ++j) {
				for (int j2 = x; j2 < x + x_; ++j2) {
					map[j][j2] = c;
				}
			}
		}

		if (map[ys][xs] != map[yg][xg]) {
			cout << "NG" << endl;
			continue;
		}

		stack<pair<int, int> > st;
		st.push(MP(xs, ys));
		int m_c = map[ys][xs];
		bool flg = false;
		while (!st.empty()) {
			int x = st.top().first, y = st.top().second;
			st.pop();
			map_flg[y][x] = false;
			for (int i = 0; i < 4; ++i) {
				int x_ = x + x_move[i], y_ = y + y_move[i];
				if (map[y_][x_] == m_c && map_flg[y_][x_]) {
					if (y_ == yg && x_ == xg) {
						flg = true;
						break;
					}
					st.push(MP(x_, y_));
				}
			}
			if (flg) { break; }
		}

		if (flg) { cout << "OK" << endl; }
		else { cout << "NG" << endl; }
	}

	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int main(){
	int w, h, xs, ys, xg, yg, n, c, d, x, y, color;
	vector< vector< int > > field;
	queue< complex< int > > que;
	bool exist;
	
	while(cin >> w >> h, w){
		cin >> xs >> ys >> xg >> yg >> n;
		
		field.resize(w);
		for(int i = 0; i < w; ++i) field[i].resize(h);
		
		for(int i = 0; i < n; ++i){
			cin >> c >> d >> x >> y;
			
			if(d == 0){
				for(int j = 0; j < 4; ++j){
					for(int k = 0; k < 2; ++k){
						field[x + j - 1][y + k - 1] = c;
					}
				}
			}else{
				for(int j = 0; j < 2; ++j){
					for(int k = 0; k < 4; ++k){
						field[x + j - 1][y + k - 1] = c;
					}
				}
			}
		}
		
		que.push(complex< int >(xs - 1, ys - 1));
		color = field[xs - 1][ys - 1];
		exist = false;
		
		while(!que.empty()){
			complex< int > pos = que.front();
			que.pop();
			
			if(pos.real() == xg - 1 && pos.imag() == yg - 1){
				exist = true;
				break;
			}
			
			if(pos.real() > 0 && field[pos.real() - 1][pos.imag()] == color) que.push(pos + complex< int >(-1, 0));
			if(pos.real() < w - 1 && field[pos.real() + 1][pos.imag()] == color) que.push(pos + complex< int >(1, 0));
			if(pos.imag() > 0 && field[pos.real()][pos.imag() - 1] == color) que.push(pos + complex< int >(0, -1));
			if(pos.imag() < h - 1 && field[pos.real()][pos.imag() + 1] == color) que.push(pos + complex< int >(0, 1));
			
			field[pos.real()][pos.imag()] = 0;
			
			
		}
		
		cout << (exist ? "OK" : "NG") << endl;
	}
	
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<string>
	using namespace std;
	int xs,ys,w,h,n,ban[111][111],xg,yg;bool visited[101][101];
	bool dfs(int x,int y,int c){
		//cout<<x<<" "<<y<<endl;
		if(xg==x&&yg==y)return true;
		if(c-1||ban[x][y]!=c)return false;
		//if(ban[xs][ys]==0)return false;
		if(ban[x+1][y]==ban[xs][ys]&&visited[x+1][y]==false){
			visited[x+1][y]=true;
			if(dfs(x+1,y,c))return true;
		}
		if(ban[x][y+1]==ban[xs][ys]&&visited[x][y+1]==false){
			visited[x][y+1]=true;
			if(dfs(x,y+1,c))return true;
		}
		if(x>=2&&ban[x-1][y]==ban[xs][ys]&&visited[x-1][y]==false){
			visited[x-1][y]=true;
			if(dfs(x-1,y,c))return true;
		}
		if(y>=2&&ban[x][y-1]==ban[xs][ys]&&visited[x][y-1]==false){
			visited[x][y-1]=true;
			if(dfs(x,y-1,c))return true;
		}
		return false;
	}


int main(){

	while(cin>>w>>h&&w&&h){
	cin>>xs>>ys>>xg>>yg>>n;
	for(int i=0;i<101;i++)
	for(int j=0;j<101;j++)ban[i][j]=-1,visited[i][j]=false;
	
	for(int i=0;i<n;i++){
		int c,d,x,y;
		cin>>c>>d>>x>>y;
		if(!d){
			for(int i=x;i<x+4;i++){
				for(int j=y;j<y+2;j++){
					ban[i][j]=c;
				}
			}
		}
		else{
		for(int i=x;i<x+2;i++){
				for(int j=y;j<y+4;j++){
					ban[i][j]=c;
				}
			}
		}
		}
		if(dfs(xs,ys,ban[xs][ys]))cout<<"OK"<<endl;
	else cout<<"NG"<<endl;
	}
	return 0;
	}