merge sort for ikezawa-san 2

kagero.rb

module Enumerable
  def merge(*other)
    return to_enum(__method__, *other) unless block_given?
    inputs = [self, *other]
    while ! inputs.keep_if {|it| it.peek rescue nil}.empty?
      yield(inputs.min_by {|it| it.peek}.next)
    end
  end

  def split_for_shuffle(n = 1000000)
    return to_enum(__method__, n) unless block_given?
    each_slice(n) do |ary|
      yield(ary.sort)
    end
  end
  
  def uniq_0
    return to_enum(__method__) unless block_given?
    last = nil
    each do |curr|
      next if last == curr
      yield(curr)
      last = curr
    end
  end
end

if __FILE__ == $0
  fname = 'kagero_0_000'
  fnames = ARGF.each_line.split_for_shuffle(1000).map {|n|
    fname = fname.succ
    File.open(fname, 'w') {|fp| n.each {|line| fp.puts(line)}}
    fname
  }

  splited = fnames.map {|fn|
    File.open(fn).each_line
  }

  [].merge(*splited).uniq_0 do |it|
    puts it
  end
end