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<bits/stdc++.h>
using namespace std;
int vx[4]={1,0,-1,0};int vy[4]={0,1,0,-1};int flag=0;int board[102][102]={0};vector<pair<int,int> > com;
queue<pair<pair<int,int>,int > > qp;int num=0;
pair<pair<int,int>,int > now;
int check(int i){
  if(now.second!=board[now.first.second+vy[i]][now.first.first+vx[i]])
    return 0;
  for(int j=0;j<com.size();j++)
    if(now.first.second+vy[i]==com[j].second&&now.first.first+vx[i]==com[j].first)
      return 0;
  return 1;
}
int main(){
  int w,h;
  while(cin>>w>>h,w+h!=0){
    flag=0;num=0;
    com.clear();
    while(!qp.empty())
      qp.pop();
    int xs,ys,xg,yg;
    for(int i=0;i<h+2;i++)
      for(int j=0;j<w+2;j++)
	board[i][j]=0;
    cin>>xs>>ys;cin>>xg>>yg;
    int n,c,d,x,y;
    cin>>n;
    for(int i=0;i<n;i++){
      cin>>c>>d>>x>>y;
      for(int j=0;j<2;j++){
	for(int k=0;k<4;k++){
	  if(d==0)
	    board[y+j][x+k]=c;
	  else
	    board[y+k][x+j]=c;
	}
      }
    }
    qp.push(make_pair(make_pair(xs,ys),board[ys][xs]));
    while(!qp.empty()){
      now=qp.front();
      qp.pop();
      for(int i=0;i<4;i++){
	num++;
	if(check(i)==1){
	  qp.push(make_pair(make_pair(now.first.first+vx[i],now.first.second+vy[i]),now.second));
	  com.push_back(make_pair(now.first.first+vx[i],now.first.second+vy[i]));
	  if(now.first.first+vx[i]==xg&&now.first.second+vy[i]==yg){
	    flag=1;
	    break;
	  }
	}
      }
      if(flag==1){cout<<"OK"<<endl;break;}
      if(num==10000){cout<<"NG"<<endl;break;}
    }
  }
  return 0;
}

C++: #include <iostream>
using namespace std;
 
int C[102][102];
int ans;
int xg,yg;
 
void meiro(int W,int H,int c){
  if(W==xg && H==yg){
    ans = 1;
    return;
  }
 
  if(C[W][H]!=c){
    return;
  }
 
  C[W][H] = '.';
 
  meiro(W-1,H  ,c);
  meiro(W  ,H+1,c);
  meiro(W+1,H  ,c);
  meiro(W  ,H-1,c);
}
 
int main(){
  while(1){
    for(int i=0;i<102;i++){
      for(int j=0;j<102;j++){
        C[i][j] = 0;
      }
    }
     
    int w,h;
    cin >> w >> h;
 
    if(w==0 && h==0){
      break;
    }
 
    int xs,ys;
    cin >> xs >> ys;
 
    cin >> xg >> yg;
 
    int n;
    cin >> n;
    int c[n],d[n],x[n],y[n];
 
    int cbase;
 
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
 
      if(d[i]==0){
        for(int j=x[i];j<x[i]+4;j++){
          for(int k=y[i];k<y[i]+2;k++){
            C[j][k]=c[i];
          }
        }
      }
      if(d[i]==1){
        for(int j=x[i];j<x[i]+2;j++){
          for(int k=y[i];k<y[i]+4;k++){
            C[j][k]=c[i];
          }
        }
      }
    }
    ans = 0;
 if(C[xs][ys] == 0){
      cout << "NG" << endl;
      continue;
    }
    meiro(xs,ys,C[xs][ys]);
   
    if(ans==1){
      cout << "OK" << endl;
    }else{
      cout << "NG" << endl;
    }
  }
 
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#pragma region defins
#define ll long long
#define loop(i,n) for (int i = 0; i < n; i++)
#define loops(i,f,n) for (int i = (f); i < n; i++)
#define INF 100000000000000
#define sort(a) sort(a.begin(),a.end())
#define rsort(a) sort(a.rbegin(),a.rend())
using namespace std;
#pragma endregion
int w, h, sx, sy, gx, gy, n;
vector <vector<int > > grid(105, vector<int>(105));
vector <vector<bool > > grid_visited(105, vector<bool>(105, false));
void input(int c, int d, int x, int y)
{
	if (d == 0)//yokonaga
	{
		loop(i, 2)
		{
			loop(j, 4)
			{
				grid[y + i][x + j] = c;
			}
		}
	}
	else//tatenaga
	{
		loop(i, 4)
		{
			loop(j, 2)
			{
				grid[y + i][x + j] = c;
			}
		}
	}
}
bool dfs(int nx, int ny)
{
	if (nx == gx&&ny == gy)return true;
	if (nx < 0 || ny < 0 || nx >= h || ny >= w || grid[nx][ny] == 0 || grid_visited[nx][ny])return false;
	grid_visited[nx][ny] = true;
	return (dfs(nx + 1, ny) || dfs(nx, ny + 1) || dfs(nx - 1, ny) || dfs(nx, ny - 1));
	return false;
}
int main()
{
	while (1)
	{
		cin >> w >> h;
		if (!w && !h) break;
		else
		{
			cin >> sx >> sy >> gx >> gy >> n;
			sx--; sy--; gx--; gy--;
			loop(i, n)
			{
				int c, d, x, y;
				cin >> c >> d >> x >> y;
				x--; y--;
				input(c, d, x, y);
			}
			/*loop(i, h)
			{
				loop(j, w)
				{
					cout << grid[i][j] << " ";
				}
				cout << endl;
			}*/
			cout << (dfs(sx, sy) ? "OK" : "NG") << endl;
		}
	}

}

C++: #include <iostream>
using namespace std;
int F[102][102];

void DFScolor(int X,int Y,int color,int Xg,int Yg){

	if(F[X][Y]!=color)
		return;
	
	F[X][Y]=0;
	DFScolor(X-1,Y,color,Xg,Yg);
	DFScolor(X,Y+1,color,Xg,Yg);
	DFScolor(X+1,Y,color,Xg,Yg);
	DFScolor(X,Y-1,color,Xg,Yg);
	
}


int main(){
while(1){
	int count=0;
	int H,W,xg,yg,xs,ys,n;
	cin>>H;
	if(H==0)
		count++;
	cin>>W;
	if(W==0)
		count++;
	if(count==2 || H<4 || W<4)
		return 0;
	cin>>xs>>ys;
	cin>>xg>>yg;	
	cin>>n;
	int c,d,x,y;
	int xb[n],yb[n],colo[n];
	for(int i=0;i<n;i++){
		
		cin>>c>>d>>x>>y;
		colo[i]=c;
		xb[i]=x;
		yb[i]=y;
		if(d==0){
			for(int o=y;o<y+2;o++){
				for(int j=x;j<x+4;j++){
					F[j][o]=c;
				}
			}
		}
		else if(d==1){
			for(int o=y;o<y+4;o++){
				for(int j=x;j<x+2;j++){
					F[j][o]=c;
				}
			}
		}
		
	}
	for(int o=ys;o<=yg;o++){
		for(int j=xs;j<=xg;j++){
			cout<<F[j][o];
		}
		cout<<endl;
	}	
	for(int i=0;i<n;i++){
		if(xb[i]==xs&&yb[i]==ys){
			DFScolor(xb[i],yb[i],colo[i],xg,yg);
			break;
		}
	}
	if(F[xg][yg]==0)
		cout<<"OK"<<endl;
	else
		cout<<"NG"<<endl;
	
}
	return 0;
}