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 F[102][102];

void DFS(int Y,int X,int C){
   if(F[Y][X]!=C)
      return;
   F[Y][X]=6;
   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,xg,yg,n;
   int c,d,x,y;
   while(true){
      cin >> w >> h;
      if(w==0&&h==0)
         break;
      cin >> xs >> ys;
      cin >> xg >> yg;
      cin >> n;
      for(int i=1;i<=n;i++){
         cin >> c >> d >> x >> y;
         if(d==0){
             F[y+1][x+1]=c;
             F[y+1][x+2]=c;
             F[y+1][x+3]=c;
             F[y+1][x+4]=c;  
             F[y+2][x+1]=c;
             F[y+2][x+2]=c;
             F[y+2][x+3]=c;
             F[y+2][x+4]=c;   
         }
         if(d==1){
             F[y+1][x+1]=c;
             F[y+2][x+1]=c;
             F[y+3][x+1]=c;
             F[y+4][x+1]=c;  
             F[y+1][x+2]=c;
             F[y+2][x+2]=c;
             F[y+3][x+2]=c;
             F[y+4][x+2]=c;   
         }
      }
      if(F[ys+1][xs+1]!=1&&F[ys+1][xs+1]!=2&&F[ys+1][xs+1]!=3&&F[ys+1][xs+1]!=4&&F[ys+1][xs+1]!=5)
         cout << "NG" << endl;
      else{
         DFS(ys+1,xs+1,c);
         if(F[yg+1][xg+1]==6)
            cout << "OK" << endl;
         else
            cout << "NG" << endl;
         for(int i=1;i<=w;i++)
            for(int j=1;j<=h;j++)
               F[i][j]=0;
      }
   }
   return 0;
}

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

int Board[102][102];    //Board[j, x, w][i, y, h]
bool isOK;              //迷路がOKかNGか
int xs, ys, xg, yg;     //StartとGoalの座標

void DFS(int c, int x, int y){
    if(Board[x][y] != c){
        return;
    }
    else if(x==xg && y==yg){
        isOK = true;    //Goalなら迷路はOK
        return;
    }

    Board[x][y] = 0;

    DFS(c, x+1, y  );
    DFS(c, x  , y+1);
    DFS(c, x-1, y  );
    DFS(c, x  , y-1);
}

int main(){
    int w,h;
    while(true){
        cin >> w >> h;
        if(w==0 && h==0)
            break;
        
        isOK = false;               //初期値をNGに
        for(int i=1;i<=100;i++){    //Boardの初期化
            for(int j=1;j<=100;j++)
                Board[j][i] = -1;
        } 
        cin >> xs >> ys >> xg >> yg;

        int n, c, d, x, y;
        cin >> n;
        for(int t=0;t<n;t++){
            cin >> c >> d >> x >> y;
            int wb = 2+(!d*2);      //d=0なら横長
            int hb = 2+(d*2);       //d=1なら縦長
            for(int i=0;i<hb;i++){
                for(int j=0;j<wb;j++)
                    Board[x+j][y+i] = c;
            }
        }

        DFS(Board[xs][ys], xs, ys);

        if(isOK)
            cout << "OK" << endl;
        else
            cout << "NG" << endl;
        
    }
    return 0;
}

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

int F[102][102];

void DFS(int x, int y, int c){
      if(F[x][y]!=c)
            return;

      F[x][y] = -1;

      DFS(x+1, y  , c);
      DFS(x  , y+1, c);
      DFS(x-1, y  , c);
      DFS(x  , y-1, c);
}

int main(){
      int w,h, xs,ys, xg,yg, n;
      while(1){
            cin >> w >> h;
            if(w==0)    break;
            cin >> xs >> ys;
            cin >> xg >> yg;
            cin >> n;

            int c, d, x, y;
            for(int i=1; i<=n; i++){
                  cin >> c >> d >> x >> y;
                  if(d==0){
                        for(int fx=x; fx<=x+3; fx++){
                        F[fx][y]   = c;
                        F[fx][y+1] = c;
                        }
                  }
                  else if(d==1){
                        for(int fy=y; fy<=y+3; fy++){
                        F[x][fy]   = c;
                        F[x+1][fy] = c;
                        }
                  }
            }

            DFS(xs, ys, F[x][y]);
            if(F[xg][yg]==-1)
                  cout << "OK" << endl;
            else
                  cout << "NG" << endl;
      }

      return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <bitset>
#include <set>
#include <map>
#include <stack>
#include <list>

#define rep(i,n) for(int i=0;i<n;i++)
#define REP(i,b,n) for(int i=b;i<n;i++)
#define SORT(c) sort((c).begin(),(c).end())
#define DESCSORT(c) sort(c.begin(), c.end(), greater<int>())

const float PI = 3.1415926;
static const int INFTY = (1<<30);

using namespace std;

int B[102][102];
int M[102][102];
int w, h, xs, ys, xg, yg, n, res;
 
void bfs(int x, int y, int c) {
  if(x <= 0 || y <= 0 || x > w || y > h)
    return;
  if(B[x][y] != c)
    return;
  if(M[x][y] == 1) {
    return;
  } else {
    M[x][y] = 1;
  }
  if(x == xg && y == yg) {
    res = 1;
    return; 
  }
  bfs(x+1, y, c);
  bfs(x, y+1, c);
  bfs(x-1, y, c);
  bfs(x, y-1, c);
}

int main() {
  while(cin >> w >> h, w) {
    // ?????????
    rep(i, w) {
      rep(j, h) {
        B[i][j] = 0;
        M[i][j] = 0;
      }
    }
    res = 0;
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;
    // ??????????????????
    rep(i, n) {
      int c, d, x, y;
      cin >> c >> d >> x >> y;
      
      B[x][y] = c;
      B[x+1][y] = c;
      B[x][y+1] = c;
      B[x+1][y+1] = c;
      if ( d == 0 ) {
        B[x+2][y] = c;
        B[x+3][y] = c;
        B[x+2][y+1] = c;
        B[x+3][y+1] = c;
      } else {
        B[x][y+2] = c;
        B[x][y+3] = c;
        B[x+1][y+2] = c;
        B[x+1][y+3] = c;
      }        
    }
    if(B[xs][ys] != 0)
      bfs(xs, ys, B[xs][ys]);
    if(res)
      cout << "OK" << endl;
    else
      cout << "NG" << endl;
  }
  
  return 0;
}