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From: jean-marc.alliot@irit.fr
To: Simon Cruanes <simon.cruanes.2007@m4x.org>, caml-list@inria.fr
Subject: Re: [Caml-list] Choosing a random element in a Map or a Set
Date: Thu, 18 Mar 2021 18:06:44 +0100
Message-ID: <ab290a1f-fdc0-e116-6131-f901d3afaefe@alliot.org> (raw)
In-Reply-To: <YFNhxmn8RIuzsxsf@church>

Thanks Simon. This works beautifully and without having to write a
single additional line of code. A few modifications were enough.

That's the advantage of getting old: 30 years ago I would have jumped on
my keyboard, now I realize that somebody smarter than me has probably
already solved the problem, and I just ask and wait...  😁

Also thanks to all the other people who have answered my request. It's a
pleasure, and an honor, to be still part of this community.

Le 18/03/2021 à 15:20, Simon Cruanes a écrit :
> There are some balanced trees with a weight attached to each node.
> I have an implementation in containers-data
> [signature](https://c-cube.github.io/ocaml-containers/3.2/containers-data/CCWBTree/module-type-S/index.html) .
>
> There is a random_choose function that does the traversal and exploits
> the weight to pick left/right for each node.
>
> I implemented this years ago but the comments say:
>
>     Most of this comes from "implementing sets efficiently in a functional language", Stephen Adams.
>     The coefficients 5/2, 3/2 for balancing come from "balancing weight-balanced trees"
>

  reply	other threads:[~2021-03-18 17:03 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-18  9:44 jean-marc.alliot
2021-03-18 10:06 ` François Pottier
2021-03-18 14:20   ` Simon Cruanes
2021-03-18 17:06     ` jean-marc.alliot [this message]
2021-03-18 11:10 ` Nicolas Barnier
2021-03-18 11:32   ` François Pottier
2021-03-19  1:32   ` Francois Berenger
2021-03-18 12:34 ` Ivan Gotovchits
2021-03-18 12:48 ` Ivan Gotovchits

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