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<bits/stdc++.h>
using namespace std;
#define ANSWER(x) cout<<x<<endl
#define debug(x) cout<<#x<<": "<<x
const int BA = 1000;
const int INFTY = (1<<21);
int xg,yg,w,h,gc;
int maps[101][101];
int solve(int ys,int xs);
int main(){
  int tate[2] = {2,4};
  int yoko[2] = {4,2};
  int xs,ys,n;
  int c[101],d[101],x[101],y[101];
  while(1){
    fill(maps[0],maps[101],0);
    cin >> w >> h;
    if(w==0 && h==0)break;
    cin >> xs >> ys >> xg >> yg >> n;
    xs--;ys--;xg--;yg--;
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
      x[i]--;y[i]--;
    }
    for(int i=0;i<n;i++){
      for(int j=y[i];j<y[i]+tate[d[i]];j++){
	for(int k=x[i];k<x[i]+yoko[d[i]];k++){
	  if(j == ys && k == xs)gc = c[i];
	  maps[j][k] = c[i];
	}
      }
    }
    /* for(int i=0;i<h;i++){
       for(int j=0;j<w;j++){
       cout << maps[i][j];
       }
       cout << endl;
       }*///マップ確認用
    if(solve(ys,xs))cout << "OK\n";
    else cout << "NG\n";
  }
}
int solve(int ys,int xs){
  if(xs < 0 || ys < 0 || xs > w-1 || ys > h-1 || maps[ys][xs] == 0 || maps[ys][xs] != gc){
    return 0;
  }
  else if(ys == yg && xs == xg){
    return 1;
  }
  maps[ys][xs] = 0;
  return solve(ys+1,xs) + solve(ys,xs+1)+ solve(ys-1,xs) + solve(ys,xs-1);
}

C++: #include <iostream>
using namespace std;
 
class Solve{
private:
    int board[101][101];
    int board_weight;
    int board_hight;
    int start_x;
    int start_y;
    int goal_x;
    int goal_y;
    int start_color;
    const int vector_x[4] = {0, 0, -1, 1};
    const int vector_y[4] = {1, -1, 0, 0};
    bool flag = false;
    void dfs(int x, int y);
public:
    Solve(int Board_Weight, int Board_Hight, int Start_X, int Start_Y, int Goal_X, int Goal_Y);
    void set_Block(int Color, int Direction, int X, int Y);
    bool check();
};
 
Solve::Solve(int Board_Weight, int Board_Hight, int Start_X, int Start_Y, int Goal_X, int Goal_Y){
    board_weight = Board_Weight;
    board_hight  = Board_Hight;
    start_x      = Start_X;
    start_y      = Start_Y;
    goal_x       = Goal_X;
    goal_y       = Goal_Y;
}
void Solve::set_Block(int Color, int Direction, int X, int Y){
    if(X == start_x && Y == start_y){
        start_color = Color;
    }
    if(Direction == 0){
        for(int h = 0;h < 2;h++){
            for(int w = 0;w < 4;w++){
                board[Y+h][X+w] = Color;
            }
        }
    }else{
        for(int h = 0;h < 4;h++){
            for(int w = 0;w < 2;w++){
                board[Y+h][X+w] = Color;
            }
        }
    }
}
bool Solve::check(){
    Solve::dfs(start_x, start_y);
    return flag;
}
void Solve::dfs(int X, int Y){
    if(X == goal_x && Y == goal_y){
        flag = true;
        return;
    }
     
    for(int y = 0;y < 4;y++){
        for(int x = 0;x < 4;x++){
            int new_x = X + vector_x[x];
            int new_y = Y + vector_y[y];
             
            if(new_x >= 0 && new_x < board_weight){
                if(new_y >= 0 && new_y < board_hight){
                    if(start_color == board[new_y][new_x]){
                        board[Y][X] = 9;
                        dfs(new_x, new_y);
                    }
                }
            }
        }
    }
    return;
}
 
int main(){
    int w, h, sx, sy, gx, gy, n, c, d, x, y;
     
    while(cin >> w >> h){
        if(w == 0 && h == 0) break;
        cin >> sx >> sy >> gx >> gy;
        Solve s(w, h, sx, sy, gx, gy);
         
        cin >> n;
         
        for(int i = 0;i < n;i++){
            cin >> c >> d >> x >> y;
            s.set_Block(c, d, x, y);
        }
         
        if(s.check()){
            cout << "OK\n";
        }else{
            cout << "NG\n";
        }
    }
     
    return 0;
}

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-1  ,H,c);
  meiro(W,H+1 ,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] = 10;
      }
    }
 
    int xs,ys,xg,yg;
    cin >> xs >> ys >> xg >> yg;
 
    int n;
    cin >> n;
 
    int c,d,x,y;
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;
 
      if(d==0){
        for(int j=x;j<x+4;j++){
          for(int k=y;k<y+2;k++){
            C[j][k]=c;
          }
        }
      }else{
        for(int j=x;j<x+2;j++){
          for(int k=y;k<y+4;k++){
            C[j][k]=c;
          }
        }
      }
    }
 
    meiro(xs,ys,C[xs][ys]);
 
    if(C[xg][yg] == -1){
      cout << "OK" << endl;
    }else{
      cout << "NG" << endl;
    }
  }
 
  return 0;
}

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

int w,h;
int field[102][102];
int sx,sy;
int gx,gy;
int n;
int color;
bool ans;

void DFS(int x,int y)
{
	if(x == gx && y == gy){
		ans = true;
		return;
	}
	if(field[y][x] == -1)
		return;
	field[y][x] = -1;
	if(color == field[y][x-1])
		DFS(x-1,y);
	if(color == field[y][x+1])
		DFS(x+1,y);
	if(color == field[y-1][x])
		DFS(x,y-1);
	if(color == field[y+1][x])
		DFS(x,y+1);
}
int main()
{
	while(cin >> w >> h){
		if(!w&&!h)
			break;
		ans = false;
		memset(field,-1,sizeof(field));
		cin >> sx >> sy;
		cin >> gx >> gy;
		cin >> n;
		for(int i=0;i<n;i++){
			int c,d,x,y;
			cin >> c >> d >> x >> y;
			if(d == 1){
				for(int i=0;i<4;i++){
					for(int j=0;j<2;j++){
						field[y+i][x+j] = c;
					}
				}
			}
			else if(d == 0){
				for(int i=0;i<2;i++){
					for(int j=0;j<4;j++){
						field[y+i][x+j] = c;
					}
				}
			}
		}
		color = field[sy][sx];
		DFS(sx,sy);
		if(ans)
			cout << "OK" << endl;
		else
			cout << "NG" << endl;
	}
	return 0;
}