Fog Creek Puzzle Solution

fogcreek.rb

LETTERS = "acdegilmnoprstuw"

def reverse(h, str)
  if (h == 7)
    return str.reverse
  elsif (h < 7)
    return false
  end

  if ((h % 1) != 0)
    return false
  end

  0.upto(LETTERS.length - 1) do |i|
    newh = (h - i) / 37.0
    newstr = str + LETTERS[i]
    result = reverse(newh, newstr)

    if (result != false)
      return result
    end
  end
end

puts reverse(910897038977002, "")