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<utility>
#include<queue>
using namespace std;

typedef pair<int,int> P;

int main(){
  int w,h;
  int xs,ys,xg,yg;
  int n;
  int c,d,x,y;
  int grid[101][101];
  bool visit[101][101];

  for(;;){
    cin >> w >> h;
    if(!w && !h)break;

    for(int i=1;i<=h;i++)
      for(int j=1;j<=w;j++){
	grid[i][j] = 0;
	visit[i][j] = false;
      }
    cin >> xs >> ys >> xg >> yg;

    cin >> n;
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;
      if(d){
	for(int j=0;j<4;j++)
	  for(int k=0;k<2;k++)grid[y+j][x+k] = c;
      }else{
	for(int j=0;j<2;j++)
	  for(int k=0;k<4;k++)grid[y+j][x+k] = c;
      }
    }

    int color = grid[ys][xs];    
    queue<P> q;
    if(color){
      q.push(P(ys,xs));
      visit[ys][xs] = true;
      while(q.size()){
	P p = q.front();q.pop();
	y = p.first;
	x = p.second;
	
	int dx[] = {0,1,0,-1},dy[] = {-1,0,1,0};
	for(int i=0;i<4;i++){
	  int sx = x+dx[i],sy = y+dy[i];
	  if(sx<=0 || sy<=0 || w<sx || h<sy)continue;
	  if(visit[sy][sx] || grid[sy][sx]!=color)continue;
	  q.push(P(sy,sx));
	  visit[sy][sx] = true;
	}
      }
      if(visit[yg][xg])cout << "OK\n";
      else cout << "NG\n";
    }else{
      cout << "NG\n";
    }
  }
}

C++: #include<iostream>
using namespace std;
int a[101][101]={},sx,sy,gx,gy;
int f(int i,int j){
	if(i==gy && j==gx)
		return 1;
	if(a[i+1][j]==a[sy][sx])
		if(f(i+1,j)==1)
			return 1;
	if(a[i][j+1]==a[sy][sx])
		if(f(i,j+1)==1)
			return 1;
	if(a[i-1][j]==a[sx][sy])
		if(f(i-1,j)==1)
			return 1;
	if(a[i][j-1]==a[sx][sy])
		if(f(i,j-1)==1)
			return 1;
	return 0;
}
int main(){
	while(1){
		int w,h,n,c,d,x,y;
		cin>>w>>h;
		if(w==0 && h==0)
		break;
		for(int i=0;i<h;i++)
		for(int j=0;j<w;j++)
			a[i][j]=0;
		cin>>sx>>sy;
		cin>>gx>>gy;
		cin>>n;
		for(int i=0;i<n;i++){
			cin>>c>>d>>x>>y;
			if(d==0){
				for(int i=0;i<2;i++)
				for(int j=0;j<4;j++)
					a[y+i][x+j]=c;
			}
			if(d==1){
				for(int i=0;i<4;i++)
				for(int j=0;j<2;j++)
					a[y+i][x+j]=c;
			}
		}
		if(a[sx][sy]!=a[gx][gy])
		cout<<"NG"<<endl;
		else if(f(sy,sx)==0)
		cout<<"NG"<<endl;
		else if(f(sx,sy)==1)
		cout<<"OK"<<endl;
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
  
int F[105][105];
int xg,yg;
  
  
void DFS(int Y,int X,int c){
  if(F[Y][X] != c){
    return;
  }
  
  F[Y][X] = -2000;
  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;

      
    cin >> xs >> ys >> xg >> yg >> n;
    int c[n],d[n],x[n],y[n],ca;
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
    }
    for(int i=0;i<n;i++){
      if(c[i] == 0)
        ca = 10;
      else if(i == n-1)
        ca = 0;
    }
    for(int i=0; i<102; i++){
          for(int j=0; j<102; j++){
            F[i][j]=ca;
          }
    }
    for(int i=0;i<n;i++){
      if(d[i] == 0){
        for(int j=0;j<4;j++){
          F[x[i]+j][y[i]] = c[i];
          F[x[i]+j][y[i]+1] = c[i];
        }
      } else {
        for(int j=0;j<4;j++){
          F[x[i]][y[i]+j] = c[i];
          F[x[i]+1][y[i]+j] = c[i];
        }
      }
    }
 
  DFS(xs,ys,F[xs][ys]);
  
  if(F[xg][yg] == -2000){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
}

C++: #include <iostream>
using namespace std;
int board[100][100],w,h,xg,yg;
bool f(int y,int x){
	board[y][x] = 0;
	int dy[] = {-1,0,0,1},dx[] = {0,-1,1,0},i;
	if(y == yg - 1 && x == xg -1) return true;
	for(i = 0;i < 4;i++){
		if(y + dy[i] > -1 && y + dy[i] < h && x + dx[i] > -1 && x + dx[i] < w){
			if(board[y+dy[i]][x+dx[i]] == 2){
				if(f(y+dy[i],x+dx[i])) return true;
			}
		}
	}
	return false;
}
int main(){
	int xs,ys,n,i,c,d,x,y,j,k;
	while(cin >> w >> h && (w != 0 && h != 0)){
		cin >> xs >> ys;
		cin >> xg >> yg;
		cin >> n;
		for(i = 0;i < n;i++){
			cin >> c >> d >> x >> y;
			x -= 1;
			y -= 1;
			if(d == 0){
				for(j = 0;j < 2;j++){
					for(k = 0;k < 4;k++){
						board[y+j][x+k] = c;
					}
				}
			}
			else if(d == 1){
				for(j = 0;j < 2;j++){
					for(k = 0;k < 4;k++){
						board[y+k][x+j] = c;
					}
				}
			}
		}
		if(board[ys - 1][xs - 1] == 2){
			if(f(ys - 1,xs -1)) cout << "OK" << endl;
			else cout << "NG" << endl;
		}
		else cout << "NG" << endl;
		for(j = 0;j < 100;j++){
			for(i = 0;i < 100;i++){
				board[j][i] = 0;
			}
		}
	}
	return 0;
}

C++: #include<stdio.h>
#define N 100
#define M 500

void search(int map[100][100],int x,int y,int c){
  if(map[x][y]==0 || c==0)  return;
  if(map[x][y]!=c && map[x][y]!=9)  return;
  if(map[x][y]==9){
    map[x][y]=7;
    return;
  } 
  map[x][y]=7;
  search(map,x-1,y,c);
  search(map,x+1,y,c);
  search(map,x,y-1,c);
  search(map,x,y+1,c);
}

int main(void){
  int i,num,j,k,l;
  int w[N],h[N];
  int xs[N],ys[N];
  int xg[N],yg[N];
  int n[N];
  int c[N][M],d[N][M],x[N][M],y[N][M];
  int map[N][N];

  for(i=0;;i++){
    scanf("%d%d",&w[i],&h[i]);
    if(w[i]==0 && h[i]==0)  break;
    scanf("%d%d",&xs[i],&ys[i]);
    scanf("%d%d",&xg[i],&yg[i]);
    scanf("%d",&n[i]);
    for(j=0;j<n[i];j++){
      scanf("%d%d%d%d",&c[i][j],&d[i][j],&x[i][j],&y[i][j]);
    }
  }
  num=i;
  for(i=0;i<num;i++){
    for(j=0;j<w[i];j++){
      for(k=0;k<h[i];k++){
        map[j][k]=0;
      }
    }
    for(j=0;j<n[i];j++){
      if(d[i][j]==0){
        for(k=0;k<2;k++)
          for(l=0;l<4;l++)
            map[x[i][j]+l][y[i][j]+k]=c[i][j];
      }else if(d[i][j]==1){
        for(k=0;k<4;k++)
          for(l=0;l<2;l++)
            map[x[i][j]+l][y[i][j]+k]=c[i][j];
      }
    }
    map[xg[i]][yg[i]]=9;
    search(map,xs[i],ys[i],map[xs[i]][ys[i]]);
    if(map[xg[i]][yg[i]]==7)        printf("OK\n");
    else if(map[xg[i]][yg[i]]==9)   printf("NG\n");
  }
  return 0;
}