F encode(input_string)
   V count = 1
   V prev = Char("\0")
   [(Char, Int)] lst
   L(character) input_string
      I character != prev
         I prev != Char("\0")
            lst.append((prev, count))
         count = 1
         prev = character
      E
         count++
   lst.append((input_string.last, count))
   R lst

F decode(lst)
   V q = ‘’
   L(character, count) lst
      q ‘’= character * count
   R q

V value = encode(‘aaaaahhhhhhmmmmmmmuiiiiiiiaaaaaa’)
print(‘Encoded value is ’value.map(v -> String(v[1])‘’v[0]))
print(‘Decoded value is ’decode(value))