From: Niklas Frykholm <niklas@...>
Date: 2002-01-21T07:46:54+09:00
Subject: Re: Coding challenge :-)

[David Alan Black]:
> Hello --
> 
> I've posted a little coding challenge to the Ruby Garden Wiki:
> 
>   http://www.rubygarden.org/ruby?CodingChallenge0001

Sorry, I sent the wrong version. It should be:

  def parse_to_array
    numbers = {}
    split(',').each {|interval|
      if interval[/([-\d]+)-([-\d]+)/]
        $1.to_i.upto($2.to_i) {|i| numbers[i] = 1}
      else
        numbers[interval.to_i] = 1
      end
    }
    numbers.keys.sort
  end

  def expanded
    parse_to_array.join ','
  end

  def compacted
    intervals = []
    parse_to_array.each {|num|
      if intervals[0] && num == intervals[-1][1].succ
        intervals[-1][1] = num
      else
        intervals << [num,num]
      end
    }
    intervals.map {|i1, i2| "#{i1}" + (i1==i2 ? "" : "-#{i2}")}.join ','
  end

// Niklas