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From: Simon Cruanes <simon.cruanes.2007@m4x.org>
To: "François Pottier" <francois.pottier@inria.fr>
Cc: jean-marc.alliot@irit.fr, caml-list@inria.fr
Subject: Re: [Caml-list] Choosing a random element in a Map or a Set
Date: Thu, 18 Mar 2021 10:20:54 -0400
Message-ID: <YFNhxmn8RIuzsxsf@church> (raw)
In-Reply-To: <368aa12e-e819-4049-7ec5-4a3479f77bbb@inria.fr>

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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"

-- 
Simon Cruanes

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  reply	other threads:[~2021-03-18 14:21 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 [this message]
2021-03-18 17:06     ` jean-marc.alliot
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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