From: Igor Pechtchanski <pechtcha@cs.nyu.edu>
To: Richard Jones <rich@annexia.org>
Cc: Brian Hurt <bhurt@spnz.org>, caml-list@pauillac.inria.fr
Subject: Re: [Caml-list] Re: Set and Map question
Date: Mon, 20 Sep 2004 08:41:26 -0400 (EDT) [thread overview]
Message-ID: <Pine.GSO.4.61.0409200836210.12686@slinky.cs.nyu.edu> (raw)
In-Reply-To: <20040920081708.GA2792@annexia.org>
On Mon, 20 Sep 2004, Richard Jones wrote:
> On Sun, Sep 19, 2004 at 11:02:44PM -0500, Brian Hurt wrote:
> > The code is actually fairly easy. Take the length of the list. Subtract
> > one for the root node. The first (n-1)/2 elements are in the left hand
> > subtree, the last n-1-((n-1)/2) elements are in the right subtree.
>
> Wouldn't you have to iterate over the list when implementing this?
> What I mean to say is that this would work if you had a pre-sorted
> Array, but not a linked List. ?
Did the question mention anything about the space used by the algorithm?
If one is allowed O(n) temp space, then simply converting the sorted
linked List into a temp array as the first step will keep the algorithm
O(n) (constant factors aside). One would need a constant-time-access data
structure anyway, to build a balanced tree bottom-up in a functional way.
Igor
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next prev parent reply other threads:[~2004-09-20 12:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-20 2:37 [Caml-list] " Seth Fogarty
2004-09-20 3:14 ` [Caml-list] " Seth Fogarty
2004-09-20 3:56 ` skaller
2004-09-20 4:18 ` Seth Fogarty
2004-09-20 6:43 ` skaller
2004-09-20 8:32 ` Diego Olivier Fernandez Pons
2004-09-20 4:02 ` Brian Hurt
2004-09-20 8:17 ` Richard Jones
2004-09-20 12:41 ` Igor Pechtchanski [this message]
2004-09-20 12:54 ` Jean-Christophe Filliatre
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