talk_selector.rb

def select(total_talk_time, talk_list)
  time = 0
  selected_talk_list = []
  original_talk_list = talk_list.clone

  while time < total_talk_time
    if talk_list.empty?
      break
    end
    min = talk_list.min
    if (min + time) <= total_talk_time
      selected_talk_list << min
      talk_list.slice!(talk_list.index(min))
    end
    time = time + min
  end
  selected_talk_list

  selected_talk_list_size = selected_talk_list.size

  original_talk_list.combination(selected_talk_list_size).select { |ns| ns.reduce(:+) <= total_talk_time }.map { |e| e.sort! }.uniq.sort.reverse.first
end

if __FILE__ == $0
  talk_list = [30, 40, 20, 20, 30]
  total_talk_time = 120
  puts select(total_talk_time, talk_list).inspect
end