From: Benoit Daloze <eregontp@...>
Date: 2009-11-24T08:08:14+09:00
Subject: Re: Distinct Sets (#225)

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I must admit is a very elegant solution.
And it's not so slow, 0.36s with my tests and adding .map { |s|
        s.flatten.to_a*.sort*
    }, it pass all the tests without sorting.
Awesome for a Ruby-based class! A nice exemple of using forgot methods like
divide.

2009/11/23 <brabuhr@gmail.com>

> Here's my not-fast solution:
>
> require 'set'
>
> class Set
>  def intersect?(other)
>    other.each { |o| return true if include?(o) }
>    false
>  end
> end
>
> def distinct_sets(array_of_arrays)
>  set_of_sets = array_of_arrays.map{|a|
>    a.to_set
>  }.to_set
>
>  set_of_sets.divide{|i, j|
>    i.intersect?(j)
>  }.map{|s|
>    s.flatten.to_a
>  }
> end
>
> Adding the intersect? method to Set was primarily motivated by
> readability, but also provided a noticeable speed improvement over my
> original alternative (intersection.size.>).
>
>

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