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>
#include <cstring>
#include <vector>
#include <map>
#include <algorithm>

#define rep(i, j) FOR(i, 0, j)
#define FOR(i, j, k) for(int i = j; i < k; ++i)

using namespace std;

int w, h, xs, ys, xg, yg, n, c, d, x, y, b[101][101];
int dx[] = {0, -1, 0, 1}, dy[] = {-1, 0, 1, 0};

bool dfs(int x, int y){
  fprintf(stderr, "%d %d\n", x, y);
  int nx, ny;
  b[x][y] = 0;
  if(x == xg && y == yg) return true;
  bool r = 0;
  rep(i, 4){
    nx = x + dx[i]; ny = y + dy[i];
    if(nx >= 0 && nx < h && ny >= 0 && ny < w && b[nx][ny]==c)r=r||dfs(nx, ny);
  }
  return r;
}

int main(){
  while(scanf("%d %d", &w, &h) && w && h){
    memset(b, 0, sizeof(b));
    scanf("%d%d%d%d", &ys, &xs, &yg, &xg);
    scanf("%d", &n);
    rep(i, n){
      scanf("%d%d%d%d", &c, &d, &y, &x);
      rep(j, (d>0?4:2)) rep(k, (d>0?2:4)) b[x + j][y + k] = c;
    }
    rep(i, h){
      rep(j, w) printf("%d ", b[i][j]);
      puts("");
    }
    c = b[xs][ys];
    if(dfs(xs, ys)) puts("OK");
    else puts("NG");
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
#include <utility>
#include <string>

#define Pa pair<int,int>

using namespace std;

int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};

string bfs(int a[101][101], int sx, int sy, int gx, int gy, int w, int h)
{
	int s, t, m = a[sy][sx];
	bool vis[101][101];
	string str = "NG";
	queue<Pa> que;
	Pa pa;
	fill(&vis[0][0], &vis[h+1][w+1], true);
	
	que.push(Pa(sy, sx));
	vis[sy][sx] = false;
	
	while(!que.empty()){
		pa = que.front();
		que.pop();
		if(pa.first == gy && pa.second == gx){
			str = "OK";
			break;
		}
		
		for(int i = 0; i < 4; i++){
			s = pa.first + dy[i];
			t = pa.second + dx[i];
			if(1 <= s && s <= h && 1 <= t && t <= w){
				if(vis[s][t] && m == a[s][t]){
					que.push(Pa(s, t));
					vis[s][t] = false;
				}
			}
		}
	}
	
	return str;
}

int main()
{
	int a[101][101], w, h, sx, sy, gx, gy, s, t, u, v, n;
	
	while(1){
		cin >> w >> h;
		if(w == 0 && h == 0){
			break;
		}
		fill(&a[0][0], &a[h][w], 0);
		cin >> sx >> sy;
		cin >> gx >> gy;
		cin >> n;
		
		while(n--){
			cin >> s >> t >> u >> v;
			if(t == 0){
				for(int i = v; i <= v+1; i++){
					for(int j = u; j <= u+3; j++){
						a[i][j] = s;
					}
				}
			} else {
				for(int i = v; i <= v+3; i++){
					for(int j = u; j <= u+1; j++){
						a[i][j] = s;
					}
				}
			}
		}
		
		cout << bfs(a, sx, sy, gx, gy, w, h) << endl;
	}
	
	return 0;
}

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

int needleX[4] = {-1, 0, 1, 0};
int needleY[4] = {0, 1, 0, -1};

bool dfs(int x, int y, int goalx, int goaly,vector<vector<int> >& canGo){

    //??´??????????????????????????????true
    if(x == goalx && y == goaly){ return true; }

    //???????????°????????¢?´¢???????????????
    canGo[x][y] = false;

    //???????????????????????¢?´¢
    for(int i = 0; i < 4; i++){
        int nextx = x + needleX[i];
        int nexty = y + needleY[i];

        //?????????????????????
        if(canGo[nextx][nexty]){
            bool flag = dfs(nextx, nexty, goalx, goaly, canGo);
            if(flag){
                return true;
            }
        }
    }

    return false;
}


int block(int w, int h){

    //0 0??§??????
    if(w == 0 && h == 0){return 0;}

    //??????????????±??\???
    int xs, ys, xg, yg;
    int n;
    int c, d, inputX, inputY;
    vector<vector<int> > canGo(h + 2, vector<int>(w + 2, 0));
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;

    //??????????????????
    for(int i = 1; i <= n; i++){
        cin >> c >> d >> inputX >> inputY;
        if(d == 0){
            for(int j = 0; j < 4; j++){
                for(int k = 0; k < 2; k++){
                    canGo[inputY + k][inputX + j] = c;
                }
            }
        }else{
            for(int j = 0; j < 2; j++){
                for(int k = 0; k < 4; k++){
                    canGo[inputY + k][inputX + j] = c;
                }
            }
        }   
    }
    /*??????????????¨???
    cout << canGo[ys][xs] << endl;
    for(int i = 1; i <= h; i++){
        for(int j = 1; j <= w; j++){
            cout << canGo[i][j];
        }
        cout << endl;
    }
    cout << endl;
    */

    //????????????bool????????¨?????????
    int load = canGo[ys][xs];
    for(int i = 1; i <= h; i++){
        for(int j = 1; j <= w; j++){
            if(canGo[i][j] == load){
                canGo[i][j] = 1;
            }else{
                canGo[i][j] = 0;
            }
        }
    }
    
    // ??±???????????¢?´¢????????????????????????
    bool result = dfs(xs,ys,xg,yg,canGo);
    if(result){
        return 1;
    }else{
        return 2;
    }

    
}

int main(void){
    int i = 0;
    int array[30];
    int w, h;
    while(1){
        cin >> w >> h;
        array[i] = block(w, h);
        if(array[i] == 0){break;}
        i++;
    }
    for(int j = 0; j < i; j++){
        if(array[j] == 1){cout << "OK" << endl;}
        else {cout << "NG" << endl;}
    }

    return 0;
}