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 <cstring>
using namespace std;

bool b;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
int board[105][105];
int w , h , xg , yg , sc;

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 || board[tx][ty]!=sc || board[tx][ty]==0 || b ) continue;
		dfs( tx,ty );
	}
}

int main(){
	int w , h;
	while(cin >> w >> h , w||h){
		int xs , ys , 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){
				for(int k=y;k<y+2;++k){
					for(int j=x;j<x+4;++j){
						board[j][k]=c;
					}
				}
			} else {
				for(int k=y;k<y+4;++k){
					for(int j=x;j<x+2;++j){
						board[j][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 n, w, h, xs, ys, xg, yg, f[105][105] = { 0 }, dx[] = { 0,1,0,-1 }, dy[] = { 1,0,-1,0 }, used[105][105] = { 0 };
bool flag = 0;
void dfs(int y, int x) {
	for (int i = 0; i < 4; i++) {
		int nx = x + dx[i];
		int ny = y + dy[i];
		if (xg == nx&&yg == ny) {
			flag = true;
			return;
		}
		if (used[ny][nx]) continue;
		if (1 <= nx&&nx <= w && 1 <= ny&&ny <= h&&f[ny][nx]>0) {
			used[ny][nx] = 1;
			dfs(ny, nx);
		}
	}
	return;
}

int main() {
	while (1) {
		cin >> w >> h;
		if (w == 0 && h == 0) return 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 < 2; j++) {
					for (int k = 0; k < 4; k++) {
						f[y + j][x + k] = 1;
					}
				}
			}
			else {
				for (int j = 0; j < 4; j++) {
					for (int k = 0; k < 2; k++) {
						f[y + j][x + k] = 1;
					}
				}
			}
		}
		used[ys][xs] = 1;
		dfs(ys, xs);
		if (flag) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}

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<w;i++){
      for(int j=0;j<h;j++){
        C[w][h] = 0;
      }
    }
    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]==xs &&y[i]==ys){
        cbase = c[i];
      }
    }
    ans = 0;
    meiro(xs,ys,cbase);

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

  return 0;
}

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){
    	cout << 1 << endl;
        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);
        /*for(int i=1;i<w;i++){
        	for(int j=1;j<h;j++){
        		cout << map[i][j];
        	}
        	cout << endl;
        }*/
        cout << ans << endl;
    }
}