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 w, h;

int field[100][100];
int pathToGoal[100][100];

int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};

int dfs(int x, int y, int goalX, int goalY, int color) {
    pathToGoal[y][x] = 1;
    if (x == goalX && y == goalY) {
        return 1;
    }
    int res = 0;
    for (int i = 0; i < 4; ++i) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        if (0 <= nx && nx < w && 0 <= ny && ny < h && pathToGoal[ny][nx] == -1 && field[ny][nx] == color) {
            res += dfs(nx, ny, goalX, goalY, color);
        }
    }
    return res;
}

int main() {
    while (true) {
        cin >> w >> h;
        if (w == 0 && h == 0) {
            return 0;
        }

        for (int i = 0; i < 100; ++i) {
            for (int j = 0; j < 100; ++j) {
                field[i][j] = -1;
                pathToGoal[i][j] = -1;
            }
        }

        int xs, ys;
        int xg, yg;
        int n;
        cin >> xs >> ys;
        cin >> xg >> yg;
        cin >> n;
        xs--;
        ys--;
        xg--;
        yg--;
        for (int i = 0; i < n; ++i) {
            int c, d, x, y;
            cin >> c >> d >> x >> y;
            x--;
            y--;
            if (d == 0) {
                for (int p = 0; p < 2; ++p) {
                    for (int q = 0; q < 4; ++q) {
                        field[y + p][x + q] = c;
                    }
                }
            }
            else {
                for (int p = 0; p < 4; ++p) {
                    for (int q = 0; q < 2; ++q) {
                        field[y + p][x + q] = c;
                    }
                }
            }
        }

        if (dfs(xs, ys, xg, yg, field[xs][ys]) > 0) {
            cout << "OK" << endl;
        }
        else {
            cout << "NG" << endl;
        }
    }
}

C++: #include<iostream>
#include<queue>
using namespace std;
#define MAX_N 1000
int x[MAX_N][MAX_N], y[MAX_N][MAX_N];
int H, W, N, X, Y, C, D, SX, SY, GX, GY;
int main() {
	while (true) {
		cin >> W >> H;
		if (H == 0 && W == 0) { break; }
		cin >> SX >> SY >> GX >> GY >> N;
		for (int i = 0; i < MAX_N; i++) {
			for (int j = 0; j < MAX_N; j++) {
				x[i][j] = 0; y[i][j] = 0;
			}
		}
		for (int i = 0; i < N; i++) {
			cin >> C >> D >> X >> Y;
			if (D == 0) {
				for (int j = Y; j < Y + 2; j++) {
					for (int k = X; k < X + 4; k++) {
						x[j][k] = C;
					}
				}
			}
			if (D == 1) {
				for (int j = Y; j < Y + 4; j++) {
					for (int k = X; k < X + 2; k++) {
						x[j][k] = C;
					}
				}
			}
		}
		queue<pair<int, int> >Q; Q.push(make_pair(SY, SX)); y[SY][SX] = 1;
		while (!Q.empty()) {
			pair<int, int>pa = Q.front(); Q.pop();
			int a1 = pa.first; int a2 = pa.second;
			if (y[a1 - 1][a2] == 0 && a1 - 1 >= 1 && x[a1][a2] == x[a1 - 1][a2]) { y[a1 - 1][a2] = 1; Q.push(make_pair(a1 - 1, a2)); }
			if (y[a1 + 1][a2] == 0 && a1 + 1 <= H && x[a1][a2] == x[a1 + 1][a2]) { y[a1 + 1][a2] = 1; Q.push(make_pair(a1 + 1, a2)); }
			if (y[a1][a2 - 1] == 0 && a2 - 1 >= 1 && x[a1][a2] == x[a1][a2 - 1]) { y[a1][a2 - 1] = 1; Q.push(make_pair(a1, a2 - 1)); }
			if (y[a1][a2 + 1] == 0 && a2 + 1 <= W && x[a1][a2] == x[a1][a2 + 1]) { y[a1][a2 + 1] = 1; Q.push(make_pair(a1, a2 + 1)); }
		}
		if (y[GY][GX] == 1) { cout << "OK" << endl; }
		if (y[GY][GX] == 0) { cout << "NG" << endl; }
	}
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <string>
#include <sstream>
#include <algorithm>
#include <math.h>
#include <map>
#include <iomanip>
#include <vector>

using namespace std;



int w, h, xs, ys, xg, yg, n, c, d, x, y;
int board[100][100];	//添字は行、列の順
int dirx[] = {-1, 0, 0, 1};
int diry[] = {0, -1, 1, 0};
//xs,ysから接する同じ色のところを100に置き換えていく
void dfs(int x, int y)
{
	board[y][x] = 6;
	
	for (int i=0; i<4; i++)
	{
		int nx, ny;
		
		nx = x + dirx[i];
		ny = y + diry[i];
		
		if (0<=nx && nx<w && 0<=ny && ny<h && board[ny][nx]==c)
		{
			dfs(nx, ny);
		}
	}
}


int main()
{
	while (cin >> w >> h)
	{
		if (w == 0 && h == 0) break;
		
		cin >> xs >> ys >> xg >> yg >> n;
		
		//board初期化
		for (int i=0; i<h; i++)
		{
			for (int j=0; j<w; j++)
			{
				board[i][j] = 0;
			}
		}
		
		for (int i=0; i<n; i++)
		{
			cin >> c >> d >> x >> y;
			if (d == 0)
			{
				//横向き
				board[y-1][x-1] = board[y-1][x] = board[y-1][x+1] = board[y-1][x+2] = c;
				board[y][x-1] = board[y][x] = board[y][x+1] = board[y][x+2] = c;
			} else {
				//縦向き
				board[y-1][x-1] = board[y][x-1] = board[y+1][x-1] = board[y+2][x-1] = c;
				board[y-1][x] = board[y][x] = board[y+1][x] = board[y+2][x] = c;
			}
		}
		
		dfs(xs, ys);
		if (board[yg-1][xg-1] == 6)
		{
			cout << "OK" << endl;
		} else {
			cout << "NG" << endl;
		}
		
		/*
		//テスト出力
		for (int i=0; i<h; i++)
		{
			for (int j=0; j<w; j++)
			{
				cout << board[i][j];
			}
			cout << endl;
		}
		*/
	}
	
	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] = 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(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;
  }
  }
}