壊れたロボット２ #Java

　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();
    }

}