solver.rb

def char_num(n)
  return 0 if n == 'P'
  return 1 if n == 'L'
  return 2 if n == 'U'
  return 3 if n == 'S'
end
alfa = "あいうえおかきくけこさしすせそたちつてとなにぬねのはひふへほまみむめもやゆよらりるれろわをんがぎぐげござじずぜぞばびぶべぼぱぴぷぺぽ".split('')
text = "PLSUPUUSPSPLPPPLPPPLPLLUPLUUPLULPPLLPSPLPLSUPPPLPUPSPLPUPSUUPLPSPSUSPLUUPSSPPUPLPPPUPUSSPPSPPPUSPLULPULUPULLPSUPPSSSPPPUPPPLPLPUPUPPPUPUPUSPPUUSPSPSLPPPPSSSPLPLPLUPPLSPPLUSPULSPSLLPPPUPPSSPLUUPUPUPUUPPUSSPPPLLPPPPSSSPUPPPULLPULPPSPPPSSUPSSSPPLUPLPLPLLLPLLPPUPSPUUUPSUPPPLPPPUPPPLLPPLPPLLSPLLSPULUPULLPULLPULPPSLUPPUPPPUPPLULPLUPPLSLPULLPSLUPPLSPLUUPLUP"

slice_text = text.scan(/.{1,4}/)

slice_text.each_with_index.map {|c,i|
  sum = 0
  sum = sum + char_num(c[0]) * 4 ** 3
  sum = sum + char_num(c[1]) * 4 ** 2
  sum = sum + char_num(c[2]) * 4 ** 1
  sum = sum + char_num(c[3]) * 4 ** 0
  print "#{alfa[sum]}"
  print "\n" if (i+1) % 15 == 0
}