Solution for RPCFN: Fair Distribution (#6) G.Petit

fair_distribution.rb

# Author : Guillaume Petit
# Forked by Benoit Daloze

class Array
  def sum
    inject(0) { |sum, e| sum + e }
  end
end

class FairDistribution
  attr_reader :distribution

  def initialize(jobs, nb_of_presses)
    @jobs = jobs.sort.reverse # The longest jobs first
    
    @distribution = Array.new(nb_of_presses) { [] }

    @ideal_balance = @jobs.sum.to_f / nb_of_presses

    balance # the real deal
  end

  def time_required
    @distribution.map(&:sum).max
  end

  private
  def balance
    @jobs.each { |job| find_place_for(job) }
  end

  # try to find a place (distribution) by first looking for an "ideal" place
  # and if not found, use the smallest simulated time
  def find_place_for(job)
    if ideal = @distribution.find { |press| press.sum + job == @ideal_balance }
      puts :ideal
      ideal << job
    else
      @distribution.min_by(&:sum) << job
    end
  end
end