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 weight, hight;
int g[101][101];
int sc;
int sx, sy, gx, gy;
bool flag = false;
const int vx[4] = {0, 0, -1, 1};
const int vy[4] = {1, -1, 0, 0};
 
void dfs(int x, int y){
    if(x == gx && y == gy){
        flag = true;
        return;
    }
    
    g[y][x] = -1;
    
    for(int i = 0;i < 4;i++){
        int nx = x + vx[i];
        int ny = y + vy[i];
         
        if(nx >= 0 && nx < weight && ny >= 0 && ny < hight && g[ny][nx] == sc){
            dfs(nx, ny);
        }
    }
    return;
}
 
int main(){ 
    while(1){
        int n, c, d, x, y;
        flag = false;
        g[101][101] = {};
        
        cin >> weight >> hight;
 
        if(weight == 0 && hight == 0){
            break;
        }
         
        cin >> sx >> sy >> gx >> gy >> n;
         
        for(int i = 0;i < n;i++){
            cin >> c >> d >> x >> y;
             
            if(d == 0){
                for(int h = 0;h < 2;h++){
                    for(int w = 0;w < 4;w++){
                        g[y+h][x+w] = c;
                    }
                }
            }else{
                for(int h = 0;h < 4;h++){
                    for(int w = 0;w < 2;w++){
                        g[y+h][x+w] = c;
                    }
                }
            }
        }
         
        sc = g[sy][sx];
        dfs(sx, sy);
         
        if(flag){
            cout << "OK" << endl;
        }else{
            cout << "NG" << endl;
        }
    }
     
    return 0;
}

C++: #include <iostream>
#include <sstream>
#include <vector>
#include <list>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <algorithm>
#include <numeric>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
using namespace std;

const int size = 101;
int B[size][size];
int V[size][size];

typedef pair <int, int> PII;
typedef queue <PII> QUEUE;

int main() {
    int w, h;
    while ( cin >> w >> h && w && h ) {
        for ( int i = 0; i < h; ++ i ) {
            for ( int j = 0; j < w; ++ j ) {
                B[i][j] = 0;
                V[i][j] = 0;
            }
        }
        int xs, ys, xg, yg;
        cin >> xs >> ys >> xg >> yg;
        xs --;
        ys --;
        xg --;
        yg --;
        int n;
        cin >> n;
        for ( int i = 0; i < n; ++ i ) {
            int c, d, x, y;
            cin >> c >> d >> x >> y;
            x --;
            y --;
            for ( int j = 0; j < ( d ? 4 : 2 ); ++ j ) {
                for ( int k = 0; k < ( d ? 2 : 4 ); ++ k ) {
                    int nx = x + k;
                    int ny = y + j;
                    B[ny][nx] = c;
                }
            }
        }

        // for ( int i = 0; i < h; ++ i ) {
        //             for ( int j = 0; j < w; ++ j ) {
        //                 cout << B[i][j];
        //             }
        //             cout << endl;
        //         }
        //         cout << endl;

        if ( ! B[ys][xs] || ! B[yg][xg] ) {
            cout << "NG" << endl;
            continue;
        }
        
        PII start( xs, ys );
        V[ys][xs] = 1;
        QUEUE Q;
        Q.push( start );
        bool flag = true;
        while ( ! Q.empty() ) {
            PII node = Q.front();
            Q.pop();

            int x = node.first;
            int y = node.second;
            const int dx[4] = { 1, -1, 0, 0 };
            const int dy[4] = { 0, 0, 1, -1 };

            if ( x == xg && y == yg ) {
                cout << "OK" << endl;
                flag = false;
                break;
            }
            
            for ( int i = 0; i < 4; ++ i ) {
                int nx = x + dx[i];
                int ny = y + dy[i];
                if ( nx < 0 || nx >= w ) continue;
                if ( ny < 0 || ny >= h ) continue;
                if ( B[y][x] != B[ny][nx] ) continue;
                if ( V[ny][nx] ) continue;
                V[ny][nx] = 1;
                PII next( ny, nx );
                Q.push( next );
            }
        }

        if ( flag ) cout << "NG" << endl;
    }
    return 0;
}

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

int f[102][102];

void draw(int c,int d,int x,int y){
    if(d){
        for(int i=x;i<x+2;i++){
            for(int j=y;j<y+4;y++){
                f[i][j]=c;
            }
        }
    }else{
        for(int i=x;i<x+4;i++){
               for(int j=y;j<y+2;y++){
                    f[i][j]=c;
                }
        }
    }
}

bool judge(int c,int x,int y){
    if(c==f[x][y]){
        return true;
    }
    return false;
}

bool DFS(int xs,int ys,int xg,int yg){
    if(xs!=xg||ys!=yg){
        if(judge(f[xs][ys],xs+1,ys)){
            if(DFS(xs+1,ys,xg,yg)){
                return true;
            }
        }
          
        if(judge(f[xs][ys],xs-1,ys)){
            if(DFS(xs-1,ys,xg,yg)){
                return true;
            }
        }
        if(judge(f[xs][ys],xs,ys+1)){
            if(DFS(xs,ys+1,xg,yg)){
                return true;
            }
        }
        if(judge(f[xs][ys],xs,ys-1)){
            if(DFS(xs,ys,xg,yg-1)){
                return true;
            }
        }
        if(judge(f[xs][ys],xs+1,ys)&&judge(f[xs][ys],xs-1,ys)&&judge(f[xs][ys],xs,ys+1)&&judge(f[xs][ys],xs,ys-1)){
            return false;
        }
    }
    return true;
}

int main(){
    int w,h;
    int xs,ys;
    int xg,yg;
    int n;
    int c;
    int d,x,y;
    while(1){
        cin>>w>>h;
        if(w==0&&h==0)  break;
        cin>>xs>>ys;
        cin>>xg>>yg;
        cin>>n;

        for(int i=0;i<n;i++){
            cin>>c>>d>>x>>y;
            draw(c,d,x,y);
        }
        if(DFS(xs,ys,xg,yg)){
            cout<<"OK"<<endl;
        }else{
            cout<<"NG"<<endl;
        }
    }
    return 0;
}