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];

bool DFS(int Y, int X, int C, int yg, int xg)
{
  if(Y == yg && X == xg)
    return true;
  if(F[Y][X]!=C)
    return false;

  F[Y][X] = 0;

  bool tmp = 0;
  tmp += DFS(Y-1, X, C, yg, xg);
  tmp += DFS(Y+1, X, C, yg, xg);
  tmp += DFS(Y, X-1, C, yg, xg);
  tmp += DFS(Y, X+1, C, yg, xg);
  return tmp;
}

int main()
{
  while(1){
    F[102][102] = {};

    int w, h;
    cin >> w >> h;

    if(w == 0 && h == 0)
      return 0;

    int xs, ys;
    cin >> xs >> ys;

    int xg, yg;
    cin >> xg >> yg;

    int n;
    cin >> n;

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

    bool res = DFS(ys, xs, F[ys][xs], yg, xg);

    if(res)
      cout << "OK" << endl;
    else
      cout << "NG" << endl;
  }
}

C++: #include <iostream>
#include<queue>
#include<string.h>
using namespace std;
#define TATE 1
#define YOKO 0
int main(void){
    int map[101][101];
    int board[101][101];
    int T[]={0,-1,1,0};
    int Y[]={1,0,0,-1};
    int w,h,xs,xg,ys,yg,n,color,muki,x,y;
    struct ST {
        int x;
        int y;
    };
    ST RE;
    ST GO;
    queue <ST> Q;
    while(1){
        memset(map,0,sizeof(map));
        memset(board,0,sizeof(board));
        cin>>w>>h;
        if(w==0&&h==0)break;
        cin>>xs>>ys>>xg>>yg>>n;
        for(int i=0;i<n;i++){
            cin>>color>>muki>>x>>y;
            if(muki==YOKO){
                for(int j=0;j<4;j++){
                    board[y][x+j]=board[y+1][x+j]=color;
                }
            }
            else{
                for(int j=0;j<4;j++){
                    board[y+j][x]=board[y+j][x+1]=color;
                }
            }
        }
       /* for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                cout<<board[i][j];
            }
            cout<<endl;
        }*/
        RE.x=xs;
        RE.y=ys;
        map[ys][xs]=1;
        Q.push(RE);
        int flag=0;
        while(!Q.empty()){
            RE=Q.front();
            Q.pop();
            if(RE.x==xg&&RE.y==yg&&board[RE.y][RE.x]==board[yg][xg]){
                flag=1;
                //cout<<RE.x<<" "<<RE.y<<endl;
                break;
            }
            else{
                for(int i=0;i<4;i++){
                    GO=RE;
                    if(GO.x+Y[i]>0&&GO.y+T[i]>0&&GO.x+Y[i]<101&&GO.y+T[i]<101&&board[GO.y+T[i]][GO.x+Y[i]]==board[yg][xg]&&map[GO.y+T[i]][GO.x+Y[i]]!=1){
                        GO.x+=Y[i];
                        GO.y+=T[i];
                        map[GO.y][GO.x]=1;
                        Q.push(GO);
                    }
                }
            }
        }
       /* for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                cout<<board[i][j];
            }
            cout<<endl;
        }*/
        if(flag==1){
            cout<<"OK"<<endl;
        }
        else{
            cout<<"NG"<<endl;
        }
    }
    
}

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

int f[102][102];

void DFS(int x,int y,int c){
    if(f[x][y]!=c)  return;

    f[x][y]=10;
    DFS(x+1,y,c);
    DFS(x-1,y,c);
    DFS(x,y+1,c);
    DFS(x,y-1,c);
}

int main(){
    int w,h;
    int xs,ys;
    int xg,yg;
    int n;
    while(true){
        cin>>w>>h;
        if(w+h==0)  break;
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                f[i][j]=-1;
            }
        }
        cin >> xs >> ys;
        cin >> xg >> yg;
        cin >> 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++){
                    for(int k = 0; k<2; k++){
                        f[x+j][y+k] = c;
                    }
                }
            }else{
                for(int j = 0; j<2; j++){
                    for(int k = 0; k<4; k++){
                        f[x+j][y+k] = c;
                    }
                }
            }
        }
        DFS(xs,ys,f[xs][ys]);
        if(f[xg][yg]==10){
            cout<<"OK"<<endl;
        }else{
            cout<<"NG"<<endl;
        }
    }
    return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int field[101][101],b[101][101],X,Y,n,dx[4]={0,1,0,-1},dy[4]={1,0,-1,0},I,sX,sY,gX,gY,ans,sgc;
int func(int x,int y){
	for(I=0;I<4;I++){
		int xx=x+dx[I];
		int yy=y+dy[I];
		if(xx>0&&yy>0&&xx<=X&&yy<=Y&&field[xx][yy]==sgc&&b[xx][yy]==0){
			if(xx==gX&&yy==gY){
				if(ans==-1)ans=b[x][y];
				else ans=min(b[x][y]+1,ans);
			}
			else{
			b[xx][yy]=b[x][y]+1;
			func(xx,yy);
			}
		}
	}
	return 0;
}
int main(){
	int i,i2,c,d,x,y;
	cin>>X>>Y;
	while(X!=0){
		cin>>sX>>sY>>gX>>gY>>n;
		ans=-1;
		for(i=1;i<=100;i++){
			c=0;
			d=0;
			x=0;
			y=0;
			for(i2=1;i2<=100;i2++){
				field[i][i2]=0;
				b[i][i2]=0;
			}
		}
		for(i=1;i<=n;i++){
			cin>>c>>d>>x>>y;
			if(d==0){
				field[x][y]=c;
				field[x+1][y]=c;
				field[x+2][y]=c;
				field[x+3][y]=c;
				field[x][y+1]=c;
				field[x+1][y+1]=c;
				field[x+2][y+1]=c;
				field[x+3][y+1]=c;
			}
			else{
				field[x][y]=c;
				field[x][y+1]=c;
				field[x][y+2]=c;
				field[x][y+3]=c;
				field[x+1][y]=c;
				field[x+1][y+1]=c;
				field[x+1][y+2]=c;
				field[x+1][y+3]=c;
			}
		}
		/*for(i=1;i<=Y;i++){
			for(i2=1;i2<=X;i2++)cout<<field[i2][i];
			cout<<endl;
		}*/
		sgc=field[sX][sY];
		func(sX,sY);
		if(ans==-1)cout<<"NG"<<endl;
		else cout<<"OK"<<endl;
		cin>>X>>Y;
	}
}