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<string>
#include<string.h>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<stdlib.h>
#include<queue>
#include<map>
#include<vector>
#include<list>
#include<stack>
#include<functional>

using namespace std;

#define all(c) (c).begin(), (c).end()
#define rep(i,n) for(int i=0;i<n;i++)

typedef unsigned long long ull; typedef long long ll;

const int INF=100000000; int dx[4]={1,0,-1,0}; int dy[4]={0,1,0-1};

typedef pair<int ,int > P;

char maze[105][105];

int sx,sy; int gx,gy; int w,h;

char sc; //スタート地点のカラー

//stdin //stdout

void dfs(int x,int y) { maze[x][y]='9';

for(int i=0;i<4;i++) { int nx=x+dx[i]; int ny=y+dy[i];

if(0<=nx && nx<=w && 0<=ny && ny<=h &&maze[nx][ny] != '0'&&maze[nx][ny] != '9') { dfs(nx,ny); }

} return ; }

void solve() {

rep(i,101) rep(j,101) maze[i][j]='0';

int n; char c; int d; int x,y;

cin>>sy>>sx; cin>>gy>>gx;

cin>>n;

rep(i,n) { cin>>c>>d>>y>>x;

if(d==1) { rep(i,4) { rep(j,2) { maze[x+i][y+j]=c;

} } } else if (d==0) { rep(i,2) { rep(j,4) { maze[x+i][y+j]=c;

} } }

} //6 6 //1 1 //3 6 //2 //1 0 1 1 //1 1 3 3 // rep(i,w+1) // { // rep(j,h+1) // { // cout<<maze[i][j]; //// } // cout<<endl; // } //// cout<<maze[gx][gy]<<endl;

if(maze[sx][sy]=='0') { cout<<"NG"<<endl; return; } else { sc=maze[sx][sy]; dfs(sx,sy); }

//rep(i,w+1) //{ // rep(j,h+1) // { // cout<<maze[i][j];

// } // cout<<endl; //}

if(maze[gx][gy]=='9') { cout<<"OK"<<endl; return; } else { cout<<"NG"<<endl; return; }

}

int main() {

while(cin>>w>>h) { if(w==0 && h==0) { return 0; } else { solve(); } }

return 0; }

C++: #include <iostream>
struct point{
	int x;
	int y;
};
int m[101][101];
int w,h,r;
point gp;
void dfs(int x,int y,int c){
	if(!(x-gp.x)&&!(y-gp.y))r=1;
	if(x>0&&m[x-1][y]==c)m[x-1][y]=0,dfs(x-1,y,c);
	if(x<w&&m[x+1][y]==c)m[x+1][y]=0,dfs(x+1,y,c);
	if(y>0&&m[x][y-1]==c)m[x][y-1]=0,dfs(x,y-1,c);
	if(y<h&&m[x][y+1]==c)m[x][y+1]=0,dfs(x,y+1,c);
	return ;
}

int main(){
	//whÍ{[hÌå«³AnÍubNÌÂ
	int n,c,d;
	//spÍX^[gn_ÌÀWAgpÍS[n_ÌÀW
	point sp,bp;
	
	while(1){
		for(int y=0;y<101;y++){
			for(int x=0;x<101;x++){
				m[x][y] = 0;
			}
		}
		r=0;
		std::cin>>w>>h;
		if(!w&&!h)return 0;
		std::cin>>sp.x>>sp.y;
		std::cin>>gp.x>>gp.y;
		std::cin>>n;
		for(int i=0;i<n;i++){
			std::cin>>c>>d>>bp.x>>bp.y;
			int bw,bh;
			d?bw=2,bh=4:bh=2,bw=4;
			for(int y=bp.y;y<=bp.y+bh;y++){
				for(int x=bp.x;x<=bp.x+bw;x++){
					m[x][y] = c;
				}
			}
		}
		if(m[sp.x][sp.y])dfs(sp.x,sp.y,m[sp.x][sp.y]),m[sp.x][sp.y] = 0;
		if(r)std::cout<<"OK"<<std::endl;
		else{std::cout<<"NG"<<std::endl;}
	}
}

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

int n, w, h, xs, ys, xg, yg, f[105][105] = { 0 }, dx[] = { 0,1,0,-1 }, dy[] = { 1,0,-1,0 }, used[105][105] = { 0 }, color = 0;
bool flag;
void dfs(int y, int x) {
	for (int i = 0; i < 4; i++) {
		int nx = x + dx[i];
		int ny = y + dy[i];
		if (xg == nx&&yg == ny) {
			flag = true;
			return;
		}
		if (used[ny][nx]) continue;
		if (1 <= nx&&nx <= w && 1 <= ny&&ny <= h&&f[ny][nx] == color) {
			used[ny][nx] = 1;
			dfs(ny, nx);
		}
	}
	return;
}

int main() {
	while (1) {
		for (int i = 0; i < 105; i++) {
			for (int j = 0; j < 105; j++) {
				f[i][j] = 0;
			}
		}
		flag = false;
		cin >> w >> h;
		if (w == 0 && h == 0) return 0;
		cin >> xs >> ys >> xg >> yg >> n;
		for (int i = 0; i < n; i++) {
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			if (d == 0) {
				for (int j = 0; j < 2; j++) {
					for (int k = 0; k < 4; k++) {
						f[y + j][x + k] = c;
					}
				}
			}
			else {
				for (int j = 0; j < 4; j++) {
					for (int k = 0; k < 2; k++) {
						f[y + j][x + k] = c;
					}
				}
			}
		}
		used[ys][xs] = 1;
		color = f[ys][xs];
		dfs(ys, xs);
		if (color == 0) {//?????????????????????????????????
			cout << "NG" << endl; continue;
		}
		if (flag) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int field[100][100],b[100][100],X,Y,n,dx[4]={0,1,0,-1},dy[4]={1,0,-1,0},I,sX,sY,gX,gY,ans=999999,sgc;
int func(int x,int y){
	for(I=0;I<4;I++){
		int xx=x+dx[I];
		int yy=y+dy[I];
		if(xx==gX&&yy==gY){
			ans=min(b[x][y]+1,ans);
		}
		if(xx>0&&yy>0&&xx<=X&&yy<=Y&&field[xx][yy]==sgc&&b[xx][yy]==0){
			b[xx][yy]=b[x][y]+1;
			func(xx,yy);
		}
	}
	return 0;
}
int main(){
	int i,i2,c,d,x,y;
	cin>>X>>Y;
	while(X!=0){
		cin>>sX>>sY>>gX>>gY>>n;
		ans=999999;
		for(i=1;i<100;i++){
			c=0;
			d=0;
			x=0;
			y=0;
			for(i2=1;i2<100;i2++){
				field[i][i2]=0;
			}
		}
		for(i=1;i<=n;i++){
			cin>>c>>d>>x>>y;
			if(d==0){
				field[x][y]=c;
				field[x+1][y]=c;
				field[x+2][y]=c;
				field[x+3][y]=c;
				field[x][y+1]=c;
				field[x+1][y+1]=c;
				field[x+2][y+1]=c;
				field[x+3][y+1]=c;
			}
			else{
				field[x][y]=c;
				field[x][y+1]=c;
				field[x][y+2]=c;
				field[x][y+3]=c;
				field[x+1][y]=c;
				field[x+1][y+1]=c;
				field[x+1][y+2]=c;
				field[x+1][y+3]=c;
			}
		}
		sgc=field[sX][sY];
		func(sX,sY);
		if(ans==999999)cout<<"NG"<<endl;
		else cout<<"OK"<<endl;
		cin>>X>>Y;
	}
}