euler23.rb

   1 load 'divisors.rb'
   2
   3 require 'logger'
   4 $log = Logger.new(STDERR)
   5 $log.level = Logger::WARN
   6
   7 abundant_numbers = (12..28124).select {|i| i.abundant?}
   8
   9 candidates = Array.new(28124) {|i| i}
  10 candidates[0] = nil
  11
  12 abundant_numbers.each_index do |i|
  13   j = abundant_numbers.length - 1
  14   while j >= i
  15     candidates[abundant_numbers[i] + abundant_numbers[j]] = nil
  16     $log.info {"Eliminating #{abundant_numbers[i] + abundant_numbers[j]} as the sum of #{abundant_numbers[i]} and #{abundant_numbers[j]} (i=#{i}, j=#{j})" }
  17     j -= 1
  18   end
  19 end
  20
  21 # p candidates.compact
  22 p candidates.compact.reduce(:+)
  23
  24 $log.close