单词逆序，符号不逆序

这是百度的一道算法题，很简单，当时却没做出来，太紧张了。

package 单词逆序;

import java.util.Scanner;

public class Nixu {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        
        String string = new String();
        Scanner in = new Scanner(System.in);
        
        string = in.nextLine();
        
        String []str = string.split(" ");
        String danci = new String();
        String s = new String();
        for(int i=str.length-1;i>=0;i--)
        {
            char []x = str[i].toCharArray();
            int flag=0;
            for(int j=0;j<x.length;j++)
            {
                if(x[j]<'A' || x[j]>'z')
                {
                    flag=1;
                }
            }
            if(flag==0)
                danci = danci +str[i]+" ";
        }
        
        for(int i=0;i<str.length;i++)
        {
            char []x = str[i].toCharArray();
            int flag=0;
            for(int j=0;j<x.length;j++)
            {
                if(x[j]<'A' || x[j]>'z')
                {
                    flag=1;
                }
            }
            if(flag==1)
                s =s +str[i]+" ";
        }
        
        
        System.out.println(danci+s);

    }

}