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 F[102][102] = { 0 };

void DFS(int Y, int X, int c) {
	//cout << Y << " " << X << endl;
	if (F[Y][X] != c)
		return;
	F[Y][X] = 10;
	DFS(Y - 1, X, c);//???
					 //DFS(Y - 1, X+1, A_ito);//??????
	DFS(Y, X + 1, c);//???
					 //DFS(Y + 1, X+1, A_ito);//??????
	DFS(Y + 1, X, c);//???
					 //DFS(Y + 1, X-1, A_ito);//??????
	DFS(Y, X - 1, c);//???
					 //DFS(Y - 1, X-1, A_ito);//??????
}


int main()
{
	int xs, ys, xg, yg, n;
	int c, d, x, y;
	int W = 1, H = 1;

	while (true) {
		cin >> W >> H;
		if ((W != 0) && (H != 0)) {
			break;
		}
		cin >> xs >> ys >> xg >> yg >> n;
		for (int i = 1;i <= n;i++) {
			cin >> c >> d >> x >> y;
			if (d == 0) {
				F[x][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y] = c;
				F[x + 1][y + 1] = c;
				F[x + 2][y] = c;
				F[x + 2][y + 1] = c;
				F[x + 3][y] = c;
				F[x + 3][y + 1] = c;
			}
			if (d == 1) {
				F[x][y] = c;
				F[x + 1][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y + 1] = c;
				F[x][y + 2] = c;
				F[x + 1][y + 2] = c;
				F[x][y + 3] = c;
				F[x + 1][y + 3] = c;
			}
		}
		if (F[ys][xs] != 0)
			DFS(ys, xs, F[ys][xs]);

		if (F[yg][xg] == F[ys][yg]) {
			cout << "OK" << endl;
		}
		else { cout << "NG" << endl; }
		for (int i = 0;i <= H;i++) {
			for (int j = 0;j <= W;j++) {
				F[i][j] = 0;
			}
		}

	}

	return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <queue>
using namespace std;
class node{
public:
	int x,y;
	void set(int xx,int yy){
		x = xx;
		y = yy;
	}
	bool check(int w,int h){
		if(x>=0&&y>=0){
			if(x<=w&&y<=h) return true;
		}
		return false;
	}
	
};

int main(){
	
	int w,h,xs,ys,xg,yg,n,c,dir,x,y;
	int i,j;
	int color[101][101];
	int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};
	bool visited[101][101];
	queue<node> q;
	node a;

	scanf("%d%d",&w,&h);
	scanf("%d%d",&xs,&ys);
	scanf("%d%d",&xg,&yg);
	scanf("%d",&n);
	while(n--){
		scanf("%d%d",&c,&dir,&x,&y);
		if(dir==0){
			for(i=0;i<2;i++){
				for(j=0;j<4;j++) color[x+j][y+i] = c;
			}
		}
		else{
			for(i=0;i<2;i++){
				for(j=0;j<4;j++) color[x+i][y+j] = c;
			}
		}
	}
	a.set(xs,ys);
	
	q.push(a);
	visited[a.x][a.y]=true;
	while(!q.empty()){
		a = q.front();
		q.pop();
		for(int i=0;i<4;i++){
			a.x += dx[i];
			a.y += dy[i];
			if(!a.check(w,h)&&(color[xs][ys]==color[a.x][a.y])&&!visited[a.x][a.y]){
				q.push(a);
				if(a.x==xg&&a.y==yg) break;
				visited[a.x][a.y] = true;
			}
		}
	}
	if(visited[xg][yg]) printf("OK\n");
	else printf("NG\n");
	
	return 0;
}

C++: #include <iostream>
using namespace std;
 
int F[105][105];
int xg,yg;
int flag;
 
void DFS(int Y,int X,int c){
  if(F[Y][X] != c){
    return;
  }
  if(Y == xg && X == yg){
     flag = 1;
     return;
  }
  F[Y][X] = -1;
  DFS(Y-1,X  ,c);
  DFS(Y  ,X+1,c);
  DFS(Y+1,X  ,c);
  DFS(Y  ,X-1,c);
}
 
 
int main(){
  int w,h,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]=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<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;
        }
      }
    }
  flag = 0;
  DFS(xs,ys,F[xs][ys]);
  if(flag == 1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
  return 0;
}

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

int board[101][101];
int xg , yg;
int w, h;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
int sc;
bool b;

void dfs(int x , int y){
	if(x==xg&&y==yg) {b=true;return;}
	for(int i=0;i<4;++i){
		int tx=x+dx[i];
		int ty=y+dy[i];
		if(tx<0||ty<0||tx>=w||ty>=h) continue;
		if(board[tx][ty]!=sc|| board[tx][ty]==0) continue;
		if(b) continue;
		dfs(tx,ty);
	}
}

int main(){
	while(cin >> w >> h , w||h){
		int xs , ys;
		int n;
		b=false;
		memset(board,0,sizeof(board));
		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 k=0;k<2;++k){
					for(int j=0;j<4;++j){
						board[x+j][y+k]=c;
					}
				}
			} else {
				for(int k=0;k<4;++k){
					for(int j=0;j<2;++j){
						board[x+j][y+k]=c;
					}
				}
			}
		}
		sc=board[xs][ys];
		int gc=board[xg][yg];
		if(sc!=gc) {}
		else dfs(xs,ys);
		cout << ( b ? "OK" : "NG") << endl;
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
 
int C[102][102];
int ans;
int xg,yg;
 
void meiro(int W,int H,int c){
  if(W==xg && H==yg){
    ans = 1;
    return;
  }
 
  if(C[W][H]!=c){
    return;
  }
 
  C[W][H] = 0;
 
  meiro(W-1,H  ,c);
  meiro(W  ,H+1,c);
  meiro(W+1,H  ,c);
  meiro(W  ,H-1,c);
}
 
int main(){
  while(1){
    for(int i=0;i<102;i++){
      for(int j=0;j<102;j++){
        C[i][j] = 0;
      }
    }
     
    int w,h;
    cin >> w >> h;
 
    if(w==0 && h==0){
      break;
    }
 
    int xs,ys;
    cin >> xs >> ys;
 
    cin >> xg >> yg;
 
    int n;
    cin >> n;
    int c[n],d[n],x[n],y[n];
 
    int cbase;
 
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
 
      if(d[i]==0){
        for(int j=x[i];j<x[i]+4;j++){
          for(int k=y[i];k<y[i]+2;k++){
            C[j][k]=c[i];
          }
        }
      }
      if(d[i]==1){
        for(int j=x[i];j<x[i]+2;j++){
          for(int k=y[i];k<y[i]+4;k++){
            C[j][k]=c[i];
          }
        }
      }
    }
    ans = 0;
 if(C[xs][ys] == 0){
      cout << "NG" << endl;
      continue;
    }
    meiro(xs,ys,C[xs][ys]);
   
    if(ans==1){
      cout << "OK" << endl;
    }else{
      cout << "NG" << endl;
    }
  }
 
  return 0;
}