Champagne Solution

champagne.rb

if ARGV[0].nil?
  puts "Usage:\n\truby #{__FILE__} {bad bottle#|test}"
  exit
end

def guess_bottle(bad_bottle, silent=false)
  waiters = []
  (0..9).each do |waiter_number|
    waiters[waiter_number] = []
    (0..999).each do |bottle|
      if (bottle & (2 ** waiter_number)) != 0
        waiters[waiter_number] << bottle
      end
    end
  end

  puts "Who got sick from bottle #{bad_bottle}?" unless silent
  sick_waiters = []

  waiters.each_with_index do |waiter,index|
    if waiter.include? bad_bottle
      puts "Waiter #{index} got sick." unless silent
      sick_waiters << index
    end
  end

  sick_waiters.inject(0) { |accum, waiter| accum + (2 ** waiter) }
end

if ARGV[0] != 'test'
  bad_bottle = ARGV[0].to_i
  puts "Based on the waiters that got sick, the bad bottle is #{guess_bottle(bad_bottle)}"
else
  (0..999).each do |bottle|
    if bottle != guess_bottle(bottle, true)
      puts "Failed on #{bottle}!"
      exit
    end
  end
  puts "No bottles failed!"
end