import java.util.ArrayList;

public class Unique
{
    private boolean memberOf2(int x, ArrayList<Integer> list)
    {
        if (list.size() == 0) return false;
        else {
            int first = list.get(0);
            list.remove(0);
            
            return (x == first) || memberOf2(x, list);
        }
    }
    
    private boolean memberOf(int x, ArrayList<Integer> list)
    {
        ArrayList<Integer> temp = (ArrayList<Integer>) list.clone();
        return memberOf2(x, temp);
    }
    
    private ArrayList<Integer> unique(ArrayList<Integer> list)
    {
        if (list.size() <= 1) return list;
        else {
            int first = list.get(0);
            list.remove(0);
            
            ArrayList<Integer> ulist = unique(list);  // rest of list
            
            if (memberOf(first, ulist)) return ulist;
            else {
                ulist.add(0, first);  // put back the first element
                return ulist;
            }
        }
    }
    
    public static void main(String args[])
    {
        Unique u = new Unique();
        ArrayList<Integer> numbers = new ArrayList<Integer>();
        
        numbers.add(4);
        numbers.add(3);
        numbers.add(1);
        numbers.add(2);
        numbers.add(4);
        numbers.add(2);
        numbers.add(4);
        numbers.add(5);
        
        System.out.print("Original list:");
        for (Integer i : numbers) System.out.printf("%2d", i);
        System.out.println();
        
        numbers = u.unique(numbers);
        
        System.out.print("  Unique list:");
        for (Integer i : numbers) System.out.printf("%2d", i);
        System.out.println();
    }
}