[racket-dev] union-find

Thanks. That's a bug.

uf-set-canonical! changes the canonical element of the set (without
affecting the identity of the set).

Robby


On Tue, Jan 29, 2013 at 4:13 PM, Danny Yoo <dyoo at hashcollision.org> wrote:

> On Tue, Jan 29, 2013 at 2:51 PM, Robby Findler
> <robby at eecs.northwestern.edu> wrote:
> > I've just pushed an implementation of the union-find algorithm to the
> data/
> > collection. I didn't do it quite the way wikipedia recommends, but
> instead
> > made the sets be little containers whose canonical element can be
> mutated.
>
> Code reviewing...
>
>
> I don't understand line 31 yet.
>
>
> http://git.racket-lang.org/plt/blob/33747ec9abc5f03d1b838aae11474351d5a6b534:/collects/data/union-
> find.rkt#l31
>
>
> How can the rank decrease back to one?  Isn't that supposed to be this
> instead?
>
>     (set-uf-set-rank! a (add1 a-rank))
>
>
>
> I'm assuming that uf-set-x is either going to be another uf-set, or a
> box.  Is that right?
>
>
> I do not understand what uf-set-canonical! is for yet; the test case
> doesn't tell me too much.
>
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