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 w,h,xs,ys,xg,yg,n;
int map[101][101];
string ans;
char start;
void fun(int y,int x){
    if(map[y][x]==start){
        map[y][x]=7;
    }
    else
        return;
    if(x<1||w<x||y<1||h<y)
        return;
    if(map[y][x]==map[yg][xg]){
        ans="OK";
        return;
    }
    fun(y,x+1);
    fun(y,x-1);
    fun(y+1,x);
    fun(y-1,x);
}
void mc(){
    int c,d,x,y;
    for(int i=0;i<n;i++){
        cin >> c >> d >> x >> y;
        if(d==0){
            for(int j=0;j<2;j++){
                for(int k=0;k<4;k++){
                    map[y+j][x+k]=c;
                }
            }
        }
        else{
            for(int j=0;j<4;j++){
                for(int k=0;k<2;k++){
                    map[y+j][x+k]=c;
                }
            }
        }
    }
}
int main(){
    while(cin >> w >> h,w){
    	ans="NG";
        cin >> xs >> ys >> xg >> yg >> n;
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                map[i][j]=0;
            }
        }
        mc();
        start=map[ys][xs];
        if(map[ys][xs]==0||map[yg][xg]==0);
        else
        	fun(ys,xs);
        cout << ans << endl;
    }
}

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;
        break;
      }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 <cstdio>
#include <queue>

using namespace std;

int w,h;
bool** flags;
char** map;

class Point{
public:
	int X,Y;
};

template <class T> T** NewArray(int w,int h){
	T** r = new T*[w];
	for(int i=0;i<w;i++){
		r[i] = new T[h];
		for(int j=0;j<h;j++){
			r[i][j] = 0;
		}
	}
	return r;
}

template <class T> void RemoveArray(T** array,int w,int h){
	for(int i=0;i<h;i++){
		delete[] array[i];
	}
	delete[] array;
}

bool Check(int x,int y,int c){
	if(x<0){return false;}
	if(y<0){return false;}
	if(x>=w){return false;}
	if(y>=h){return false;}
	if(flags[x][y]){return false;}
	if(map[x][y] != c){return false;}
}

bool Solve(int sx,int sy,int gx,int gy){
	char c = map[sx][sy];
	queue<Point> pts;
	flags = NewArray<bool>(w + 1,h + 1);
	for(int i=0;i<w;i++){
		for(int j=0;j<h;j++){
			flags[i][j] = false;
		}
	}
	Point p,pp;
	p.X = sx;
	p.Y = sy;
	pts.push(p);
	flags[sx][sy] = true;
	
	bool res = false;
	
	while(pts.size() > 0){
		p = pts.front();
		pts.pop();
		if(flags[gx][gy] == true){
			res = true;
			break;
		}
		pp = p;
		pp.X -= 1;
		if(Check(pp.X,pp.Y,c)){ pts.push(pp); flags[pp.X][pp.Y]=true; }
		pp = p;
		pp.X += 1;
		if(Check(pp.X,pp.Y,c)){ pts.push(pp); flags[pp.X][pp.Y]=true; }
		pp = p;
		pp.Y -= 1;
		if(Check(pp.X,pp.Y,c)){ pts.push(pp); flags[pp.X][pp.Y]=true; }
		pp = p;
		pp.Y += 1;
		if(Check(pp.X,pp.Y,c)){ pts.push(pp); flags[pp.X][pp.Y]=true; }
	}
	
	RemoveArray<bool>(flags,w + 1,h + 1);
	return res;
}

int main(){
	int xs,ys,xg,yg;
	
	while(scanf("%d %d",&w,&h) && w && h){
		w+=1;
		h+=1;
		map = NewArray<char>(w + 1,h + 1);
		scanf("%d %d %d %d",&xs,&ys,&xg,&yg);
		xs -= 1;
		ys -= 1;
		xg -= 1;
		yg -= 1;
		int n;
		scanf("%d",&n);
		int c,d,x,y;
		int xx,yy;
		for(int j=0;j<h;j++){
			for(int i=0;i<w;i++){
				//printf("%d ",map[i][j]);
				map[i][j] = 0;
			}
			//printf("\n");
		}
		
		for(int i=0;i<n;i++){
			scanf("%d %d %d %d",&c,&d,&x,&y);
			if(d == 0){
				xx = 4;
				yy = 2;
			}else{
				xx = 2;
				yy = 4;
			}
			x-=1;
			y-=1;
			for(int j=0;j<xx;j++){
				for(int k=0;k<yy;k++){
					//printf("(%2d+%2d,%2d+%2d) = %d\n",k,j,y,k,c);
					map[x+j][y+k] = c;
				}
			}
		}
		for(int j=0;j<h;j++){
			for(int i=0;i<w;i++){
				//printf("%d ",map[i][j]);
			}
			//printf("\n");
		}
		
		
		if(Solve(xs,ys,xg,yg)){
			printf("OK\n");
		}else{
			printf("NG\n");
		}
		RemoveArray<char>(map,w + 1,h + 1);
	}
}

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] = '.';

  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;
    }

    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];
          }
        }
      }

      if(x[i]==1 &&y[i]==1){
        cbase = c[i];
      }
    }

    meiro(xs,ys,cbase);

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

  return 0;
}