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>
#include<utility>
#include<queue>
using namespace std;

typedef pair<int,int> P;

int main(){
  int w,h;
  int xs,ys,xg,yg;
  int n;
  int c,d,x,y;
  int grid[101][101];
  bool visit[101][101];

  for(;;){
    cin >> w >> h;
    if(!w && !h)break;

    for(int i=1;i<=h;i++)
      for(int j=1;j<=w;j++){
	grid[i][j] = 0;
	visit[i][j] = false;
      }
    cin >> xs >> ys >> xg >> yg;

    cin >> n;
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;
      if(d){
	for(int j=0;j<4;j++)
	  for(int k=0;k<2;k++)grid[y+j][x+k] = c;
      }else{
	for(int j=0;j<2;j++)
	  for(int k=0;k<4;k++)grid[y+j][x+k] = c;
      }
    }

    int color = grid[ys][xs];

    queue<P> q;
    q.push(P(ys,xs));

    while(q.size()){
      P p = q.front();q.pop();
      y = p.first;
      x = p.second;
      if(yg == y && xg == x){
	cout << "OK\n";
	q.push(P(y,x));
	break;
      }
      visit[y][x] = true;
     
      int dx[] = {0,1,0,-1},dy[] = {-1,0,1,0};
      for(int i=0;i<4;i++){
	int sx = x+dx[i],sy = y+dy[i];
	
	if(sx<0 || sy<0 || w<=sx || h<=sy)continue;
	
	if(visit[sy][sx] || grid[sy][sx]!=color)continue;
	q.push(P(sy,sx));
      }
    }
    if(q.empty())cout << "NG\n";
  }
}

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] = 0;
 
  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]==1){
        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]==0){
        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 <vector>

using namespace std;

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

bool dfs(int x,int y,int xg,int yg,vector<vector<bool> > &map){
  if(x==xg && y==yg) return true;

  map[x][y]=false;

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

    if(map[nextx][nexty]){
      bool flag=dfs(nextx,nexty,xg,yg,map);
      if(flag) return true;
    }
  }
  return false;
    
}

int main(){
    while(true){
        int W,H;
        cin >> W >> H;
        if(W==0 && H==0)break;
        
        int xs,ys,xg,yg;
        cin >> xs >> ys;
        cin >> xg >> yg;
        int n;
        cin >> n;
        vector<vector<int> > cmap(W+2,vector<int>(H+2,0));
	vector<vector<bool> > map(W+2,vector<bool>(H+2,false));

	for(int i=0;i<n;i++){
	  int color,d,x,y;
	  cin >> color >> d >> x >> y;
	  for(int j=0;j<2;j++){
            for(int k=0;k<4;k++){
	      if(d==1)cmap[x+j][y+k]=color;
	      else cmap[x+k][y+j]=color;
	    }
	  }
	}
	/*
	for(int i=0;i<W+2;i++){
	  for(int j=0;j<H+2;j++){
	    cout << " " << cmap[i][j];
	  }
	  cout << endl;
	} 
	*/ 
        int c=cmap[xs][ys];
	for(int i=1;i<=W;i++){
	  for(int j=1;j<=H;j++){
	    if(cmap[i][j]==c)map[i][j]=true;
	  }
	}
	if(!(map[xs][ys] && map[xg][yg])){
	  cout << "NG" << endl;
	  return 0;
	}
	/*
	for(int i=0;i<W+2;i++){
	  for(int j=0;j<H+2;j++){
	    if(map[i][j])cout << ".";
	    else cout << "#";
	  }
	  cout << endl;
	}
	cout << endl;
	*/
        bool flag=dfs(xs,ys,xg,yg,map);
        if(flag) cout << "OK" << endl;
        else cout << "NG" << endl;
	
    }
  return 0;
}

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;
	if(F[xg][yg]!=0)
		cout<<"NG"<<endl;
	
}
	return 0;
}