SumCheckerHash

SumCheckerHash.rb

class SumCheckerHash
  
  def initialize(file_name)
    @hsh = {}
    File.open(file_name).each{|line| @hsh[line.to_i] = @hsh[line.to_i].nil? ? 1 : (@hsh[line.to_i]+1)}
  end
  
  def check(sum)
    @hsh.each_key{|i| return true if @hsh.has_key?(sum - i) && ((2*i != sum) || (@hsh[i] > 1))}
    return false
  end
    
end

require 'test/unit'

class SumCheckTest < Test::Unit::TestCase

@@test = {
        231552=>true,
        234756=>false,
        596873=>true,
        648219=>true,
        726312=>true,
        981237=>false,
        988331=>true,
        1277361=>false,
        1283379=>false
        }
        
  def test_01_verify
    sch = SumCheckerHash.new('input.txt')
    @@test.each do|key, val|
      assert_equal(val, sch.check(key))
    end
  end 
  
  def test_02_productivity
    puts
    sch = SumCheckerHash.new('input.txt')
    @@test.each do|key, val|
      ts1 = Time.now.to_f
      puts key.to_s + " - " + (sch.check(key) ? "yes" : "no") 
      ts2 = Time.now.to_f
      puts "elapsed: " + (ts2 - ts1).to_s + " s"
    end
  end

end

if (ARGV[0])
  sch = SumCheckerHash.new('input.txt')
  puts sch.check(ARGV[0].to_i) ? "yes" : "no"
  exit 0
else
  puts "Haven't got a valid sum value to check, loading tests..."
  puts "=" * 45
end

Call with a number parameter runs corresponding sum checking.
Call without parameters runs tests (verification and productivity).