1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
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codewords = []
class Integer
def rotate_left(bits, width = bit_width)
bits %= width
(self << bits | self >> (width - bits)) & ((1 << width) - 1)
end
end
(2**8).times do |candidate|
valid_candidate_p = true
8.times do |bits|
rotated_candidate = candidate.rotate_left(bits, 8)
valid_candidate_p = false if codewords.include?(rotated_candidate)
end
codewords << candidate if valid_candidate_p
end
p codewords
puts codewords.length
#=> [0, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 37, 39, 43, 45, 47, 51, 53, 55, 59, 61, 63, 85, 87, 91, 95, 111, 119, 127, 255]
#=> 36
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