Re: store or clone the Iterator

From:

Piotr Kobzda <pikob@gazeta.pl>

Newsgroups:

comp.lang.java.programmer

Date:

Mon, 04 Sep 2006 23:50:27 +0200

Message-ID:

<edi733$5bg$1@inews.gazeta.pl>

p7371464@yahoo.com.tw wrote:

[...]

But the above code can not work correctly, have any method to store the
ListIterator variable while
scan the list ?

No.

But your goal can be achieved without of it, using only two independent
iterators. See implementation:

     public static <T> T removeFirstMin(
             LinkedList<T> list, Comparator<? super T> c) {
         int left = list.size();
         ListIterator<T> fit = list.listIterator();
         ListIterator<T> bit = list.listIterator(left);
         T f = fit.next();
         T b = bit.previous();
         for (; left > 1; --left) {
             if (c.compare(f, b) <= 0) {
                 b = bit.previous();
             } else {
                 f = fit.next();
             }
         }
         fit.remove();
         return f;
     }

Which can be applied into your scenario this way:

     removeFirstMin(list, new Comparator<Integer>() {

         public int compare(Integer k1, Integer k2) {
             int v1 = f(k1);
             int v2 = f(k2);
             return (v1<v2 ? -1 : (v1==v2 ? 0 : 1));
         }

     });

HTH,
piotr