Vanadium

'''
  author: _where
  Simple sexy solution that shows a lil bit of panties
'''
def solution(s)
  rand_shift = 1
  mask = 3
  mask_values = Hash.new(0)
  palindrome_count = 0

  for i in 0...s.length
    ord_diff = s[i].ord - '0'.ord
    mask_values[mask] += 1
    mask ^= (rand_shift << ord_diff)
    palindrome_count += mask_values[mask]

    (0..9).each do |j|
      palindrome_count += mask_values[mask ^ (rand_shift << j)]
    end
  end

  palindrome_count % 1000000007
end