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BITS = 8
class Integer
def rotate_left(bits, width = bit_width)
bits %= width
(self << bits | self >> (width - bits)) & ((1 << width) - 1)
end
end
candidates = (0...(2**BITS)).to_a
(2**BITS).times do |candidate|
next if candidates[candidate].nil?
(1...BITS).each do |bits|
candidates[candidate.rotate_left(bits, BITS)] = nil
end
end
codewords = candidates.compact
p codewords
puts codewords.length
#=> [1, 3, 5, 7, 9, 11, 13, 15, 19, 21, 23, 25, 27, 29, 31, 37, 39, 43, 45, 47, 53, 55, 59, 61, 63, 87, 91, 95, 111, 127]
#=> 30
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