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;

class Solve{
private:
    int board[110][110];
    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 - 1;
    start_y      = Start_Y - 1;
    goal_x       = Goal_X - 1;
    goal_y       = Goal_Y - 1;
}
void Solve::set_Block(int Color, int Direction, int X, int Y){
    X -= 1; Y -= 1;
    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()
{
    while(true){
        int w, h, sx, sy, gx, gy, n, c, d, x, y;
        
        cin >> w >> h;
        if(w != 0 && h != 0){
            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() == true){
                cout << "OK\n";
            }else{
                cout << "NG\n";
            }
        }else{
            break;
        }
    }
    
    return 0;
}

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

char HW[102][102];

void DFS(int Y,int X,char c)
{
	if(HW[Y][X]=='0'||HW[Y][X]!=c)
		return;

	HW[Y][X]='0';
	
	DFS(Y-1,X,c);
	DFS(Y,X+1,c);
	DFS(Y+1,X,c);
	DFS(Y,X-1,c);
}	
	
int main()
{
	int H,W;
	cin>>H>>W;

	for(int y=1;y<=H+1;y++){
		for(int x=1;x<=W;x++){
			cin>>HW[y][x];
			if(HW[y][1]=='0'&&HW[y][2]=='0'){
				break;
			}
		}
		if(HW[y][1]=='0'&&HW[y][2]=='0'){
			break;
		}
	}
	
	int count=0;
	for(int y=1;y<=H;y++){
		for(int x=1;x<=W;x++){
			if((HW[y][x]=='@')||(HW[y][x]=='#')||(HW[y][x]=='*')){
				count++;
				DFS(y,x,HW[y][x]);
			}
		}
	}
	
	cout<<count<<endl;

	return 0;
}

C++: #include<iostream>
#include<map>

int field[102][102];//y,x
bool flag;
int sx,sy,gx,gy,col;
std::map<int, bool> memo;

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

void DFS(int x, int y){
	if(field[y][x] != col || memo[1000*x+y])
		return;
	if(x == gx && y == gy){
		flag = true;
		return;
	}
	memo[1000*x+y] = true;
	DFS(x+1, y);
	if(flag)
		return;
	DFS(x, y+1);
	if(flag)
		return;
	DFS(x-1, y);
	if(flag)
		return;
	DFS(x, y-1);
}

int main(){
	int n,c,d,bx,by;
	while(true){
		flag = false;
		erase();
		memo.clear();

		std::cin >> c >> d;
		if(!c && !d)
			return 0;

		std::cin >> sx >> sy;
		std::cin >> gx >> gy;

		std::cin >> n;
		for(int i=0; i<n; i++){
			std::cin >> c >> d >> bx >> by;
			if(d==0)
				for(int h=by; h<by+2; h++)
					for(int w=bx; w<bx+4; w++)
						field[h][w] = c;
			else
				for(int h=by; h<by+4; h++)
					for(int w=bx; w<bx+2; w++)
						field[h][w] = c;
		}

		col = field[gy][gx];
		DFS(sx, sy);
		if(flag)
			std::cout << "OK\n";
		else
			std::cout << "NG\n";
	}
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
#include<vector>
#include<algorithm>
#define F first
#define S second 
using namespace std;
typedef pair<int,int> P;
int w,h,sx,sy,gx,gy,fc;
int imap[110][110];
const int dx[4] = {0,1,0,-1};
const int dy[4] = {1,0,-1,0};
bool found;
void Init(){
  for(int i=0;i<110;i++){
    for(int j=0;j<110;j++){
      imap[i][j] = -1;
    }
  }
}

void display(){
 for(int i=0;i<=h;i++){
      for(int j=0;j<=w;j++){
	printf("%3d ",imap[i][j]);
      }
      cout << endl;
    }
}

void draw(int c,int d,int x,int y){
  int limy,limx;
  limy = d==1?4:2;
  limx = d==1?2:4;
  for(int i=0;i<limy && i<=h;i++){
    for(int j=0;j<limx && j<=w;j++){
      imap[y+i][x+j] = c;
    }
  }
}

void rec(int px,int py){
  if(px == gx && py == gy){
    found = true;
    return;
  }
  for(int i=0;i<4;i++){
    int nx = px+dx[i], ny = py+dy[i];
    if(!found && 0<=nx && nx <=w && 0<=ny && ny<=h && imap[ny][nx] == fc){
      imap[ny][nx] = -1;
      rec(nx,ny);
    }
  }
}


bool isMaze(){
  rec(sx,sy);
  if(found)return true;
  return false;
}

int main(){
  int n,c,d,x,y;
  while(cin >> w >> h  && w && h){
    found = false;
    cin >> sx >> sy;
    cin >> gx >> gy;
    cin >> n;
    Init();
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;
      draw(c,d,x,y);
    }

    
    fc = imap[sy][sx];
    if(fc == -1)cout << "NG" << endl;
    else{
      if(isMaze())cout << "OK" << endl;
      else cout << "NG" << endl;
    }

  }
  return 0;
}