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 Array[200][200];
bool is_goal = false;
#define START 20
#define GOAL 30

void DFS(int h,int w,int c){

  if(!is_goal){

    if(Array[h][w] == GOAL){
      is_goal = true;
      return;
    }

    if(Array[h][w] != c || Array[h][w] == 0){
      return;
    }

    int tmp=Array[h][w];

    Array[h][w] = 0;

    DFS(h-1,w,tmp);
    DFS(h,w+1,tmp);
    DFS(h+1,w,tmp);
    DFS(h,w-1,tmp);
  }

}

int main(){

    while(1){
      int H,W;
      int Start[2],Goal[2];
      int BlockNum;
      int color,dir,xpos,ypos;

      is_goal = false;

      for(int i=0;i<200;i++){
        for(int j=0;j<200;j++){
          Array[i][j] = 0;
        }
      }

      cin >> H >> W;

      if(H == 0 && W == 0){
        break;
      }

      cin >> Start[0] >> Start[1];

      cin >> Goal[0] >> Goal[1];

      cin >> BlockNum;

      for(int i=0;i<BlockNum;i++){
        cin >> color >> dir >> xpos >> ypos;
        for(int i=0;i<4;i++){
          for(int j=0;j<2;j++){
            if(!dir){//?¨?
              Array[xpos+i][ypos+j] = color;
            }
            else{
              Array[xpos+j][ypos+i] = color;
            }
          }
        }
      }
      Array[Goal[0]][Goal[1]] = GOAL;
      /*for(int i=1;i<=H;i++){
        for(int j=1;j<=W;j++){
          cout << Array[i][j];
        }
        cout << endl;
      }*/

      DFS(Start[0],Start[1],Array[Start[0]][Start[1]]);

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

  }
    return 0;
}

C++: #include <iostream>
using namespace std;
int F[102][102];

void DFScolor(int X,int Y,int color,int Xg,int Yg){

	if(F[X][Y]!=color)
		return;
	
	F[X][Y]=0;
	DFScolor(X-1,Y,color,Xg,Yg);
	DFScolor(X,Y+1,color,Xg,Yg);
	DFScolor(X+1,Y,color,Xg,Yg);
	DFScolor(X,Y-1,color,Xg,Yg);
	
}


int main(){
while(1){
	int H,W,xg,yg,xs,ys,n,count=0;
	cin>>H;
	if(H==0)
		count++;
	cin>>W;
	if(W==0)
		count++;
	if(count==2)
		return 0;
	cin>>xs>>ys;
	cin>>xg>>yg;	
	cin>>n;
	int c,d,x,y;
	int xb[n],yb[n],colo[n];
	for(int i=0;i<n;i++){
		
		cin>>c>>d>>x>>y;
		colo[i]=c;
		xb[i]=x;
		yb[i]=y;
		if(d==0){
			for(int o=y;o<y+2;o++){
				for(int j=x;j<x+4;j++){
					F[j][o]=c;
				}
			}
		}
		else if(d==1){
			for(int o=y;o<y+4;o++){
				for(int j=x;j<x+2;j++){
					F[j][o]=c;
				}
			}
		}
		
	}
	
	for(int i=0;i<n;i++){
		if(xb[i]==xs&&yb[i]==ys){
			DFScolor(xb[i],yb[i],colo[i],xg,yg);
			
			break;
		}
	}
	if(F[xg][yg]==0)
		cout<<"OK"<<endl;
	else
		cout<<"NG"<<endl;
	
}
	return 0;
}

C++: #include <iostream>
using namespace std;
  
int F[105][105];
int xg,yg,w,h;
  
  
void DFS(int Y,int X,int c){
  if(F[Y][X] != c){
    return;
  }
  
  F[Y][X] = -1;
  DFS(Y+1,X  ,c);
  DFS(Y-1  ,X,c);
  DFS(Y,X+1  ,c);
  DFS(Y  ,X-1,c);
}
  
  
int main(){
  int xs,ys,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;
for(int i=0; i<105; i++){
      for(int j=0; j<105; j++){
        F[i][j]=10;
      }
    }
      
    cin >> xs >> ys >> xg >> yg >> n;
  
  
    for(int i=0;i<n;i++){
      int c,d,x,y;
      cin >> c >> d >> x >> y;
      if(c == 0)
        c = 2345;
      if(d == 0){
        for(int j=0;j<4;j++){
          F[x+j][y] = c;
          F[x+j][y+1] = c;
        }
      } else {
        for(int j=0;j<4;j++){
          F[x][y+j] = c;
          F[x+1][y+j] = c;
        }
      }
    }
 
  DFS(xs,ys,F[xs][ys]);
  
  if(F[xg][yg] == -1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
}