recurring.rb

# Project Euler 26

def recurring(number)
  remainders = Hash.new(0)
  value      = 1
  position   = 0
  length     = 0

  while value != 0 && remainders[value] == 0
    remainders[value] = position
    value             = value * 10
    value             = value % number
    position         += 1
  end

  length = position - remainders[value] if position - remainders[value] > length
  length
end

puts (1...1000).map { |d|
  [d, recurring(d)]
}.max { |a, b|
  a[1] <=> b[1]
}