Re: [Caml-list] removing an item from a list efficiently

[Oleg Trott <oleg_trott@columbia.edu>]

On Saturday 08 November 2003 05:59 am, Oleg Trott wrote:
> On Saturday 08 November 2003 03:49 am, Dustin Sallings wrote:
> > On Nov 7, 2003, at 4:46, Stefano Zacchiroli wrote:
> > > IMHO to implement an LRU policy, lists are not the best structures due
> > > to the O(n) limit above. You can consider standard heaps (assuming you
> > > have an upper bound on the number of entries) or binomial heaps (you
> > > can
> > > find an implementation in Okasaki's book).
> >
> > 	This is really what I was asking, whether ocaml lists could be
> > appropriate.
> >
> > 	I'm having difficulty figuring out how to implement a double linked
> > list, though.  I want something like this:
> >
> > type 'a link = Nothing | Link of 'a t;;
> >
> > type 'a t = {
> >      data: 'a;
> >      mutable prev: 'a link;
> >      mutable next: 'a link;
> > };;
> >
> > 	But, link and t don't know about each other.  How does one go about
> > doing this kind of thing in ocaml?
>
> I've read your mind, and I think what you are trying to do is
>
> type 'a t = {data: 'a; mutable prev: 'a option; mutable next: 'a option};;
>
> or you can just do a web search for "doubly-linked list". It's out there.

I meant 

type 'a t = {data: 'a; mutable prev: 'a t option; mutable next: 'a t option};;

-- 
Oleg Trott <oleg_trott@columbia.edu>

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