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] = { 0 };

void DFS(int Y, int X, int c) {
	//cout << Y << " " << X << endl;
	if (F[Y][X] != c)
		return;
	F[Y][X] = 10;
	DFS(Y - 1, X, c);//???
					 //DFS(Y - 1, X+1, A_ito);//??????
	DFS(Y, X + 1, c);//???
					 //DFS(Y + 1, X+1, A_ito);//??????
	DFS(Y + 1, X, c);//???
					 //DFS(Y + 1, X-1, A_ito);//??????
	DFS(Y, X - 1, c);//???
					 //DFS(Y - 1, X-1, A_ito);//??????
}


int main()
{
	int xs, ys, xg, yg, n;
	int c, d, x, y;
	int W = 1, H = 1;

	while ((W != 0) && (H != 0)) {
		cin >> W >> H;
		for (int i = 1;i <= H;i++) {
			for (int j = 1;j <= W;j++) {
				F[i][j] = 6;
			}
		}
		cin >> xs >> ys >> xg >> yg >> n;
		for (int i = 1;i <= n;i++) {
			cin >> c >> d >> x >> y;
			if (d == 0) {
				F[x][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y] = c;
				F[x + 1][y + 1] = c;
				F[x + 2][y] = c;
				F[x + 2][y + 1] = c;
				F[x + 3][y] = c;
				F[x + 3][y + 1] = c;
			}
			if (d == 1) {
				F[x][y] = c;
				F[x + 1][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y + 1] = c;
				F[x][y + 2] = c;
				F[x + 1][y + 2] = c;
				F[x][y + 3] = c;
				F[x + 1][y + 3] = c;
			}
		}
		if(F[xs][ys]!=0)
			DFS(ys, xs, F[ys][xs]);

		if (F[yg][xg] == F[ys][yg]) {
			cout << "OK" << endl;
		}
		else { cout << "NG" << endl; }
		for (int i = 0;i <= H;i++) {
			for (int j = 0;j <= W;j++) {
				F[i][j] = 0;
			}
		}
		
	}

	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> P;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int main() {
    while (true) {
        int w, h;
        cin >> w >> h;
    
        if (w==0 && h==0) {
            break;
        }
    
        int xs, ys;
        cin >> xs >> ys;
        xs -= 1;
        ys -= 1;
        
        int xg, yg;
        cin >> xg >> yg;
        xg -= 1;
        yg -= 1;
    
        int S[h][w];
    
        for (int i=0; i<h; i++) {
            for (int j=0; j<w; j++) {
                S[i][j] = -1;
            }
        }
    
        int n;
        cin >> n;
        
        for (int i=0; i<n; i++) {
            int ci, di, xi, yi;
            cin >> ci >> di >> xi >> yi;
            xi -= 1;
            yi -= 1;
            
            if (di==0) {
                for (int i=yi; i<yi+2; i++) {
                    for (int j=xi; j<xi+4; j++) {
                        S[i][j] = ci;
                    }
                }
            }
            else {
                for (int i=yi; i<yi+4; i++) {
                    for (int j=xi; j<xi+2; j++) {
                        S[i][j] = ci;
                    }
                }
            }
        }
        
        if (S[ys][xs]==-1) {
            cout << "NG" << endl;
            continue;
        }
        
        int visited[h][w];
        
        for (int i=0; i<h; i++) {
            for (int j=0; j<w; j++) {
                visited[i][j] = 0;
            }
        }
        
        queue<P> q;
        q.push(P(ys, xs));
        visited[ys][xs] = 1;
        
        while (q.size()) {
            P p = q.front();
            q.pop();
            int cy = p.first;
            int cx = p.second;
            
            for (int i=0; i<4; i++) {
                int ny = cy+dy[i];
                int nx = cx+dx[i];
                
                if (!(0<=ny && ny<h && 0<=nx && nx<w)) {
                    continue;
                }
                
                if (visited[ny][nx]==0 && S[ny][nx]==S[cy][cx]) {
                    q.push(P(ny, nx));
                    visited[ny][nx] = 1;
                }
            }
        }
        
        if (visited[yg][xg]==1) {
            cout << "OK" << endl;
        }
        else {
            cout << "NG" << endl;
        }
    }
}

C++: #include <iostream>
#include <vector>
#include <functional>
#include <algorithm>
#include <cstring>
#include <queue>
using namespace std;

typedef pair<int, int> P;
#define rep(i,a) for(int i=0;i<(a);++i)
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl;

const int dx[] = {-1, 0, 1, 0}, dy[] = {0, -1, 0, 1};
int w,h,sx,sy,gx,gy,n;
int board[21][21];

int main()
{
    while(cin >> w >> h && w) {
        memset(board, 0, sizeof(board));
        cin >> sx >> sy >> gx >> gy >> n;
        
        int c, d, x, y;
        rep(k, n) {
            cin >> c >> d >> x >> y;
            if(d == 0)
                rep(i, 2) rep(j, 4) 
                    board[i + y][j + x] = c;
             else 
                rep(i, 4) rep(j, 2) 
                    board[i + y][j + x] = c;
        }

        int e = board[sy][sx];
        queue<P> que;
        que.push(P(sx, sy));
        bool ok = false;
        while(!que.empty()) {
            P p = que.front(); que.pop();
            x = p.first; y = p.second;
            if(x == gx && y == gy) {
                ok = true;
                break;
            }
            if(board[y][x] == -1) 
                continue;

            board[y][x] = -1;
            for(int k = 0; k < 4; k++) {
                int nx = x + dx[k];
                int ny = y + dy[k];
                if(nx >= 1 && nx <= w && ny >= 0 && ny <= h && board[ny][nx] == e) 
                    que.push(P(nx, ny));
            }
        }

        cout << ((ok) ? "OK" : "NG") << endl;
    }
}