Poj Solution 1350

http://poj.org/problem?id=1350

//* @author: <strong>Yeming&nbsp;Hu</strong>&quot;cslittleye@gmail.com&quot;
import java.util.*;
public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
    while(true)
    {
        String num = sc.next();
        if(num.equals("-1"))
        {
            break;
        }
        System.out.println("N="+num+":");
        if(num.length()!=4||(num.charAt(0)==num.charAt(1)&&
            num.charAt(1)==num.charAt(2)&& num.charAt(2)==num.charAt(3)))
        {
        System.out.println("No!!");
        }else
        {
            int count = 0;
            while(true)
        {
            char[] chs = new char[num.length()];
            for(int i = 0;i < num.length(); i++)
            {
                chs[i] = num.charAt(i);
            }
            Arrays.sort(chs);
            int small = Integer.parseInt(new String(chs));
            for(int i=0;i< chs.length/2;i++)
            {
                char temp = chs[i];
            chs[i] = chs[chs.length-1-i];
            chs[chs.length-1-i] = temp;
            }
            int big = Integer.parseInt(new String(chs));
            int diff = big - small;
            num = Integer.toString(diff);
            count++;
            System.out.println(big+"-"+small+"="+diff);
            if(diff==6174 || diff == 0)
            {
                System.out.println("Ok!! " + count  + " times");
            break;
            }
        }
        }
    }
    }
}