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 <cstdio>


int m[100][100], w, h, xs, ys, xg, yg, n;
int c, d, x, y, col;


bool solve(int X, int Y){
    if(X < 0 || X >= w || Y < 0 || Y >= h) return false;

    if(m[Y][X] != col) return false;
    if(Y == yg && X == xg) return true;

    m[Y][X] = 0;

    if(solve(X + 1, Y)) return true;
    if(solve(X - 1, Y)) return true;
    if(solve(X, Y + 1)) return true;
    if(solve(X, Y - 1)) return true;

    return false;
}


int main(){
    while(scanf("%d %d", &w, &h) != EOF){
        if(w == 0 && h == 0) break;

        for(int i = 0; i < h; i++){
            for(int j = 0; j < w; j++){
                m[i][j] = 0;
            }
        }

        scanf("%d %d", &xs, &ys);
        scanf("%d %d", &xg, &yg);
        scanf("%d", &n);

        xs--; ys--;
        xg--; yg--;

        for(int i = 0; i < n; i++){
            scanf("%d %d %d %d", &c, &d, &x, &y);
            x--; y--;

            if(d == 0){
                for(int i = y; i < y + 2; i++){
                    for(int j = x; j < x + 4; j++){
                        m[i][j] = c;
                    }
                }
            }else if(d == 1){
                for(int i = y; i < y + 4; i++){
                    for(int j = x; j < x + 2; j++){
                        m[i][j] = c;
                    }
                }
            }
        }

        col = m[ys][xs];
        if(col == 0){
            printf("NG\n");
            continue;
        }
        if(solve(xs, ys)){
            printf("OK\n");
        }else{
            printf("NG\n");
        }

    }

    return 0;
}

C++: #include <iostream>
using namespace std;
   
int F[102][102];
int xg,yg,w,h;
   
   
void DFS(int Y,int X,int c){
  //if(Y < 1 || X < 1)
    //return;
  if(F[Y][X] != c){
    return;
  }
   
  F[Y][X] = -1;
  DFS(Y+1,X  ,c);
  DFS(Y-1  ,X,c);
  DFS(Y,X+1  ,c);
  DFS(Y  ,X-1,c);
}
   
   
int main(){
  int xs,ys,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;
for(int i=0; i<102; i++){
      for(int j=0; j<102; j++){
        F[i][j] = 10;
      }
    }
       F[0][104] = 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(c == 0)
         c = 1919810;
      if(d == 0){
        for(int j=0;j<4;j++){
          F[x+j][y] = c;
          F[x+j][y+1] = c;
        }
      } else {
        for(int j=0;j<4;j++){
          F[x][y+j] = c;
          F[x+1][y+j] = c;
        }
      }
    }
  DFS(xs,ys,F[xs][ys]);
   
  if(F[xg][yg] == -1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<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] = -2;
  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;
for(int i=0; i<20; i++){
      for(int j=0; j<20; j++){
        F[i][j]=-1;
      }
    }
     
    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<4;j++){
          F[x+j][y] = c;
          F[x+j][y+1] = c;
        }
      } else {
        for(int j=0;j<4;j++){
          F[x][y+j] = c;
          F[x+1][y+j] = c;
        }
      }
    }

  DFS(xs,ys,F[xs][ys]);
 
  if(F[xg][yg] == -2){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
}

C++: #include<iostream>

using namespace std;
int board[128][128];
bool memo[128][128];
int w, h;

void judge(int x, int y, int c){
  if(x<0 || y<0 || x>=w || y>=h)return;
  if(board[y][x]!=c)return;
  if(memo[y][x])return;
  memo[y][x] = 1;
  judge(x-1, y, c);
  judge(x+1, y, c);
  judge(x, y-1, c);
  judge(x, y+1, c);
  return;
}

int main(){
  int xs, ys, xg, yg, n, i, j, k, c, d, x, y;
  while(cin>> w >> h, w+h){
    for(i=0; i<128; i++){
      for(j=0; j<128; j++){
        board[i][j] = 0;
        memo[i][j] = 0;
      }
    }
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;
    for(i=0; i<n; i++){
      cin >> c >> d >> x >> y;
      if(d==0){
        for(j=y-1; j<y+1; j++){
          for(k=x-1; k<x+3; k++){
            board[j][k] = c;
          }
        }
      }else{
        for(j=y-1; j<y+3; j++){
          for(k=x-1; k<x+1; k++){
            board[j][k] = c;
          }
        }
      }
    }
    judge(xs-1, ys-1, board[ys-1][xs-1]);
    if(memo[yg-1][xg-1]==1){
      cout << "OK" << endl;
    }else{
      cout << "NG" << endl;
    }
  }
}