壊れたロボット２

　ああああああああ！！２週目だというのに無限ループですよ！！なんの条件みすったのか・・・グラフから脱出出来なくなってる・・・

public class Main {
	boolean[][] grid = new boolean[51][51];
	int[] xMove = new int[]{1, -1, 0, 0};//xの進む距離
	int[] yMove = new int[]{0, 0, -1, 1};//yの進む距離
	double[] dir;
	
	double dfs(int n, int x, int y, double prob) {
		System.out.println(n + "ステップ目");
		double ret = 0;
		if(grid[x][y]) {
			//System.out.println("We had already visited.");
			return(0);//既に訪れたならばその連続確率は０となる
		}
		if(n == 0) {
			return(prob);//成功した事になるので、連続確率はprobで良い
		}
		System.out.println(x + ", " + y);
		for(int r = 0; r < 4; r++) {
			grid[x][y] = true;
			ret += dfs(n - 1, x + xMove[r], y + yMove[r], prob * dir[r]);
			grid[x][y] = false;
		}
		return(ret);
	}
	
	
	public double getProbability(int n, int east, int west, int south, int north) {
		dir = new double[]{((double)east)/100.0, ((double)west)/100.0, ((double)south)/100.0, ((double)north)/100.0};
		return(dfs(n, 25, 25, 1));
	}
	
	void doIt() {
		int n = 14;
		//以下２ケースにおいて無限ループ
		int x = 2, y = 2, z = 0, r = 0;
		//int x =1, y =1, z =1, r = 1;
		int east = 25*x, west = 25*y, south = 25*z, north = 25*r;
		System.out.println(getProbability(n, east, west, south, north));
	}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		new Main().doIt();
	}

}

　
　頑張らないとマズいなぁ・・・。７/11日ICPCあるのに・・・