HUD 1010老超时求高手帮忙

 import java.util.Scanner;


public class Num2 {
    static int t,y2,x2,v;
    static char[][] map;
    public static void dfs(int i,int j,int count){
        if(i<0 || j<0 || i>=map.length || j>=map[i].length){
            return;
        }
        if(((t-count)-(Math.abs(x2-i)+Math.abs(y2-j)))%2 !=0){
            return;
        }
        if((t-count)<(Math.abs(x2-i)+Math.abs(y2-j))){
            return;
        }
        if(i==x2 && j==y2 || v==1){
            if(count == t){
                v = 1;
            }
            return;
        }
        if(map[i][j] != 'X'){
            map[i][j] = 'X';
            dfs(i,j+1,count+1);
            map[i][j] = '.';
            dfs(i+1,j,count+1);
            map[i][j] = '.';
            dfs(i,j-1,count+1);
            map[i][j] = '.';
            dfs(i-1,j,count+1);
            map[i][j] = '.';
        }
    }
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            v = 0;
            int x = sc.nextInt();
            int y = sc.nextInt();
            t = sc.nextInt();
            if(x==0 && y==0 && t==0){
                break;
            }
            int x1 = 0,y1 = 0;
            map = new char[x][y];
            for(int i=0;i<x;i++){
                String n = sc.next();
                for(int j=0;j<y;j++){
                    map[i][j] = n.charAt(j);
                    if(n.charAt(j)=='S'){
                        x1 = i;
                        y1 = j;
                    }
                    if(n.charAt(j)=='D'){
                        x2 = i;
                        y2 = j;
                    }
                }
            }
            dfs(x1,y1,0);
            if(v==1){
                System.out.println("YES");
            }else{
                System.out.println("NO");
            }
        }
    }
}

有些情况运行没结果输出，求大神帮忙，谢谢