hdu1010 Tempter of the Bone(dfs) java

package dfs;

import java.util.Scanner;

public class hdu1010 {
static int d[][] = { { 1, 0 }, { -1, 0 }, { 0, 1 }, { 0, -1 } };
static int MAX_N=10;
static char map[][]=new char[MAX_N][MAX_N];
static boolean vis[][]=new boolean[MAX_N][MAX_N];
static int n,m,t,dx,dy;
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scan=new Scanner(System.in);
while(scan.hasNext()){
n=scan.nextInt();
m=scan.nextInt();
t=scan.nextInt();
if(n+m+t==0){
break;
}
scan.nextLine();
int x=0,y=0;
for(int i=0;i<n;i++){
String str=scan.nextLine();
char a[]=str.toCharArray();
for(int j=0;j<m;j++){
map[i][j]=a[j];
if(map[i][j]=='s'){
x=i;y=j;
map[i][j]='.';
}
if(map[i][j]=='D'){
dx=i;
dy=j;
}
}
}
int step=0;
init();
int res=dfs(x,y,step);
if(res==0){
System.out.println("NO");
}else{
System.out.println("YES");
}
}
}
private static int dfs(int x, int y, int step) {
// TODO Auto-generated method stub
if(step>t){
return 0;
}
if(map[x][y]=='D'){
return step;
}
for(int i=0;i<4;i++){
int sx=x+d[i][0];
int sy=y+d[i][1];
if(ok(sx,sy)&&!vis[sx][sy]&&map[sx][sy]!='X'){
vis[sx][sy]=true;
dfs(sx,sy,step+1);
vis[sx][sy]=false;
}
}
return 0;
}
private static boolean ok(int sx, int sy) {
// TODO Auto-generated method stub
if(sx<0||sx>=n||sy<0||sy>=m){
return false;
}
return true;
}
private static void init() {
// TODO Auto-generated method stub
for(int i=0;i<MAX_N;i++){
for(int j=0;j<MAX_N;j++){
vis[i][j]=false;
}
}
}

}