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 C[102][102];

void meiro(int W,int H,int c){
  if(C[W][H]!=c){
    return;
  }

  C[W][H] = -1;

  meiro(W-1,H  ,c);
  meiro(W  ,H+1,c);
  meiro(W+1,H  ,c);
  meiro(W  ,H-1,c);
}

int main(){
  while(1){
    int w,h;
    cin >> w >> h;
    if(w==0 && h==0){
      break;
    }

    for(int i=0;i<102;i++){
      for(int j=0;j<102;j++){
        C[i][j] = 0;
      }
    }

    int xs,ys,xg,yg;
    cin >> xs >> ys >> xg >> yg;

    int n;
    cin >> n;

    int c,d,x,y;
    int cbase;
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;

      if(x==xs && y==ys){
        cbase = c;
      }

      if(d==0 && c==cbase){
        for(int j=x;j<x+4;j++){
          for(int k=y;k<y+2;k++){
            C[j][k]=cbase;
          }
        }
      }
      if(d==1 && c==cbase){
        for(int j=x;j<x+2;j++){
          for(int k=y;k<y+4;k++){
            C[j][k]=cbase;
          }
        }
      }
    }
    meiro(xs,ys,cbase);

    if(C[xg][yg] == -1){
      cout << "OK" << endl;
    }
    if(C[xg][yg] != -1 || C[xs][ys] == 0){
      cout << "NG" << endl;
    }
  }

  return 0;
}

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

int F[102][102];
int xg,yg;
int flag = 0;

void DFS(int Y,int X,int c){
  if(F[Y][X]!=c){
    return;
  }
  if(Y == xg && X == yg){
    flag = 1;
  }

  F[Y][X] = 0;
  DFS(Y-1,X  ,c);
  //DFS(Y-1,X+1,c);
  DFS(Y  ,X+1,c);
  //DFS(Y+1,X+1,c);
  DFS(Y+1,X  ,c);
  //DFS(Y+1,X-1,c);
  DFS(Y  ,X-1,c);
  //DFS(Y-1,X-1,c);
}


int main(){
  int w,h,xs,ys,n;
  cin >> w >> h >> 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 {#include <iostream>
using namespace std;

int F[102][102];
int xg,yg;
int flag = 0;

void DFS(int Y,int X,int c){
  if(F[Y][X]!=c){
    return 0;
  }
  if(Y == xg && X == yg){
    flag = 1;
  }

  F[Y][X] = 0;
  DFS(Y-1,X  ,c);
  //DFS(Y-1,X+1,c);
  DFS(Y  ,X+1,c);
  //DFS(Y+1,X+1,c);
  DFS(Y+1,X  ,c);
  //DFS(Y+1,X-1,c);
  DFS(Y  ,X-1,c);
  //DFS(Y-1,X-1,c);
}


int main(){
  int w,h,xs,ys,n;
  cin >> w >> h >> 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;
      }
    }
  }

  DFS(xs,ys,F[xs][ys]);
  if(flag == 1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }

}

      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(flag == 1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }

}

C++: #include<stdio.h>
#include<iostream>
#include<list>
#include<map>
#include<vector>
#include<algorithm>
#include<string.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) range(i,0,b)
#define debug(x) cout << x << endl;
using namespace std;

int xstart, ystart;
int xgoal, ygoal;
int load;
bool check;

void answer(int maze[][1000], int x, int y){
    if(load == maze[x][y]){
        maze[x][y] = 0;
    }else{
        return;
    }
    if(x == xgoal && y == ygoal){
        cout << "OK" << endl;
        check = true;
        return;
    }
    answer(maze, x+1,y);
    answer(maze, x,y+1);
    answer(maze, x,y-1);
    answer(maze, x-1,y);
}

int main(){
    int width, height;
    int n;
    int color, direction, x, y;

    while(cin >> width >> height, height){
        int maze[1000][1000];
        check = false;
        cin >> xstart >> ystart >> xgoal >> ygoal >> n;
        rep(i,n){
            cin >> color >> direction >> x >> y;
            if(direction == 0){
                maze[x][y] = color;
                maze[x+1][y] = color;
                maze[x+2][y] = color;
                maze[x+3][y] = color;
                maze[x][y+1] = color;
                maze[x+1][y+1] = color;
                maze[x+2][y+1] = color;
                maze[x+3][y+1] = color;
            }else{
                maze[x][y] = color;
                maze[x][y+1] = color;
                maze[x][y+2] = color;
                maze[x][y+3] = color;
                maze[x+1][y+1] = color;
                maze[x+1][y+2] = color;
                maze[x+1][y+3] = color;
                maze[x+1][y+4] = color;
            }
        }
        load = maze[xstart][ystart];
        answer(maze, xstart, ystart);
        if(check == false){
            cout << "NG" << endl;
        }
    }
}

C++: #include <cstdio>
#include <cstring>
int board[100][100];
bool vst[100][100];
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
int w,h,xs,ys,xg,yg,n;
bool dfs(int x,int y) {
	if(x==xg && y==yg)
		return true;
	vst[x][y]=true;
	for(int i=0;i<4;i++) {
		int nx=x+dx[i],ny=y+dy[i];
		if(0>nx||nx>=w|0>ny||ny>=h)
			continue;
		if(board[nx][ny]!=board[xs][ys])
			continue;
		if(vst[nx][ny])
			continue;
		if(dfs(nx,ny)) return true;
	}
	return false;
}
int main() {
	while(scanf("%d %d",&w,&h),w|h) {
		scanf("%d %d",&xs,&ys); xs--;ys--;
		scanf("%d %d",&xg,&yg); xg--;yg--;
		scanf("%d",&n);
		memset(board,0,sizeof(board));
		memset(board,0,sizeof(vst));
		for(int i=0;i<n;i++) {
			int c,d,x,y;
			scanf("%d %d %d %d",&c,&d,&x,&y); x--;y--;
			if(d==0) {
				for(int i=0;i<4;i++) for(int j=0;j<2;j++)
					board[x+i][y+j]=c;
			}else {
				for(int i=0;i<2;i++) for(int j=0;j<4;j++)
					board[x+i][y+j]=c;
			}
		}
		printf("%s\n",dfs(xs,ys)?"OK":"NG");
	}
}