From: James Coglan <jcoglan@...>
Date: 2008-11-19T07:32:15+09:00
Subject: Re: Subclassing Hash to enforce value uniqueness ala key uniqueness.

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>
> Every time you add a value you iterate over all the other values to check
> whether the value is already there. This makes adding an element O(n).
> Having
> adding to a datastructure be an O(n) operation is usually a bad idea.
> Here's
> how I'd probably do it (untested):
>
> # example (elided)



This seems like a good idea, I'd have suggested the same. This is exactly
what Set in the standard library does to ensure uniqueness, it puts the
members as keys in a hash and lets Ruby sort out the hashtable as
efficiently as possible. So a pair of mutually inverted hash tables is
probably the way to go.

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