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;

int block[101][101];
int oblock[101][101];
int xg,yg,w,h;

int go (int xs, int ys) {
	//cout << xs << " " << ys << endl;
	oblock[xs][ys] = 1;
	if ( xs > w && ys > h ) {
		return 0;
	}
//	else if ( xs == w && ys == h ) {cout >> "NG" >> endl; return 0;}
	if ( xs > 1 && block[xs-1][ys] == block[xs][ys] && !oblock[xs-1][ys] ){ go( xs-1,ys ); }
	if ( ys > 1 && block[xs][ys-1] == block[xs][ys] && !oblock[xs][ys-1] ){ go( xs,ys-1 ); }
	if ( xs < w && block[xs+1][ys] == block[xs][ys] && !oblock[xs+1][ys] ){ go( xs+1,ys ); }
	if ( ys < h && block[xs][ys+1] == block[xs][ys] && !oblock[xs][ys+1] ){ go( xs,ys+1 ); }
}

int main() {
	while ( cin >> w && cin >> h ) {
		if ( !(w + h) )	break;
		//各ブロックの初期化
		for ( int i = 0; i < w; i++ ) {
			for ( int j = 0; j < h; j++ ) {
				block[i][j] = 0;
				oblock[i][j] = 0;
			}
		}
		int n,xs,ys;
		cin >> xs >> ys;
		cin >> xg >> yg;
		cin >> n;
		//各ブロックの情報の入力
		for ( int i = 0; i < n; i++ ) {
			int c,d,x,y;
			cin >> c >> d >> x >> y;
			int tate,yoko;
			if ( d ) {yoko=2;tate=4;}
			else {yoko=4;tate=2;}
			//カラーの入力
			for ( int j = x; j < x + yoko; j++ ) {
				for ( int k = y; k < y + tate; k++ ) {
					block[j][k] = c;
				}
			}
		}
		/*for ( int i = 0; i < w; i++ ) {
			for ( int j = 0; j < h; j++ ) {
				cout << block[i][j] << " ";
			}
			cout << endl;
		}
		cout << endl;*/
		//経路探索
		go ( xs, ys );
		if ( oblock[xg][yg] )	cout << "OK" << endl;
		else	cout << "NG" << endl;
		/*for ( int i = 0; i < w; i++ ) {
			for ( int j = 0; j < h; j++ ) {
				cout << oblock[i][j] << " ";
			}
			cout << endl;
		}*/
	}
}

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

int F[102][102];

bool DFS(int X, int Y, int Xg, int Yg, int c){
	if(F[Y][X] != c){
		return false;
	}else if(F[Y][X] == c && X == Xg && Y == Yg){
		return true;
	}
	F[Y][X] = -1;
	if(DFS(X, Y - 1, Xg, Yg, c)){
		return true;
	}else if(DFS(X + 1, Y, Xg, Yg, c)){
		return true;
	}else if(DFS(X, Y + 1, Xg, Yg, c)){
		return true;
	}else if(DFS(X - 1, Y, Xg, Yg, c)){
		return true;
	}
	
	return false;
}

int main(){
while(true){
	int w, h;
	cin >> w >> h;
	if(w == 0 && h == 0){
		break;
	}
	int xs, ys, xg, yg;
	cin >> xs >> ys >> xg >> yg;
	int n;
	cin >> n;
	for(int y = 0; y < 102; y++){
		for(int x = 0; x < 102; x++){
			F[y][x] = -1;
		}
	}
	for(int i = 0; i < n; i++){
		int c, d, x, y;
		cin >> c >> d >> x >> y;
		if(d == 0){
			for(int X = x; X < x + 4; X++){
				for(int Y = y; Y < y + 2; Y++){
					F[Y][X] = c;
				}
			}
		}else if(d == 1){
			for(int X = x; X < x + 2; X++){
				for(int Y = y; Y < y + 4; Y++){
					F[Y][X] = c;
				}
			}
		}
	}
	if(DFS(xs, ys, xg, yg, F[xs][ys])){
		cout << "OK" << endl;
	}else{
		cout << "NG" << endl;
	}
}
	return 0;
}

C++: #include<iostream>
#include<stack>
#include<string.h>
using namespace std;
struct ST {
	int a;
	int b;
	int c;
};
long long brock[101][101];
long long ds[101][101];
int q[4]={0,-1,0,1};
int p[4]={1,0,-1,0};
int main(){
	stack <ST> S;
	ST ma;
	ST ba;
	int w,h;//???????????§??????
	int xs,ys;//??????????????§?¨?
	int xg,yg;//??´????????§?¨?
	int n;//????????????????????°
	int c,d,x,y;//????????????????????±
	int i,j,m,check=0;
	while(1){
		memset(ds,0,sizeof(ds));
		memset(brock,0,sizeof(brock));
		cin>>w>>h;//???????????§????????\???
		if(w==0&&h==0){
			break;
		}
		cin>>xs>>ys>>xg>>yg;//??????????????¨??´???????????§?¨???\???
		cin>>n;//????????????????????°
		for(i=0;i<n;i++){
			cin>>c>>d>>x>>y;
			if(d==1){//???
				for(m=0;m<2;m++){
					for(j=0;j<4;j++){
						brock[x+m][y+j]=c;
					}
				}
			}
			else{//?¨?
				for(m=0;m<4;m++){
					for(j=0;j<2;j++){
						brock[x+m][y+j]=c;
					}
				}
			}
		}
		if(brock[xs][ys]!=brock[xg][yg]){
			cout<<"NG"<<endl;
		}
		else{
			ma.a=xs;
			ma.b=ys;
			ma.c=brock[xs][ys];
			ds[xs][ys]=1;
			S.push(ma);
			while(!S.empty()){
				ba=S.top();
				S.pop();
				ds[ba.a][ba.b]=1;
				if(ba.a==xg&&ba.b==yg){
					check=1;
				}
				if(ba.c!=brock[xg][yg]){
					S.pop();
				}
				else{
					for(i=0;i<4;i++){
						if(ba.a+p[i]>0&&ba.a+p[i]<=w&&ba.b+q[i]>0&&ba.b+q[i]<=h&&ds[ba.a+p[i]][ba.b+q[i]]==0){
							ma.a=ba.a+p[i];
							ma.b=ba.b+q[i];
							ma.c=ba.c;
							S.push(ma);
						}
					}
				}
			}
			if(check==1){
				cout<<"OK"<<endl;
			}
			else{
				cout<<"NG"<<endl;
			}
		}
	}
	return 0;
}

C++: #include<stdio.h>
#include<string.h>
void haichi(void);
void Block(int,int);
int c,d,x,y,xg,yg,M,Flag;
int MAP[101][101],MF[101][101];
int main(void)
{
	int w,h,xs,ys,n;
	while(1){
		Flag=0;
		memset(MAP,0,sizeof(MAP));
		memset(MF,0,sizeof(MF));
		scanf("%d %d",&w,&h);
		if(w == 0 && h == 0) break;
		scanf("%d %d %d %d",&xs,&ys,&xg,&yg);
		scanf("%d",&n);
		for(int i=0;i<n;i++){
			scanf("%d %d %d %d",&c,&d,&x,&y);
			haichi();
		}
		/*for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				printf("%d",MAP[i][j]);
			}
			printf("\n");
		}*/
		M = MAP[ys][xs];//
		if(MAP[ys][xs] == MAP[yg][xg])
			Block(xs,ys);
		if(Flag==1)
			printf("OK\n");
		else
			printf("NG\n");
	}
	return 0;
}

void haichi(void)
{
	if(d==0){
		MAP[y][x]=c;MAP[y][x+1]=c;MAP[y][x+2]=c;MAP[y][x+3]=c;
		MAP[y+1][x]=c;MAP[y+1][x+1]=c;MAP[y+1][x+2]=c;MAP[y+1][x+3]=c;
	}
	else if(d==1){
		MAP[y][x]=c;MAP[y][x+1]=c;
		MAP[y+1][x]=c;MAP[y+1][x+1]=c;
		MAP[y+2][x]=c;MAP[y+2][x+1]=c;
		MAP[y+3][x]=c;MAP[y+3][x+1]=c;
	}
}

void Block(int X,int Y)
{
	MF[Y][X] = 1;
	//printf("%d",M);
	if(X == xg && Y == yg)
		Flag = 1;
	if(MAP[Y-1][X] == M && MF[Y-1][X] == 0) Block(X,Y-1); //???
	if(MAP[Y+1][X] == M && MF[Y+1][X] == 0) Block(X,Y+1); //???
	if(MAP[Y][X-1] == M && MF[Y][X-1] == 0) Block(X-1,Y); //???
	if(MAP[Y][X+1] == M && MF[Y][X+1] == 0) Block(X+1,Y); //???
}