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69 lines
1.2 KiB
69 lines
1.2 KiB
input = DATA
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.readlines(chomp: true).flat_map.with_index {|row, y|
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row.chars.map.with_index {|i, x|
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[[y,x], i]
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}
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}.to_h
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freqs = input.values.uniq - %w[.]
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pp freqs.flat_map {|freq|
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antennae = input.select { _2 == freq }.keys
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antennae.combination(2).flat_map {|(ay,ax),(by,bx)|
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dy = by - ay
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dx = bx - ax
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[[ay-dy, ax-dx], [by+dy, bx+dx]]
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}.select {|yx| input.has_key?(yx) }
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}.uniq.length
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def antinodes(input, a, b)
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return enum_for(__method__, input, a, b) unless block_given?
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max_y = input.keys.map(&:first).max
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max_x = input.keys.map(&:last).max
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(ay,ax), (by,bx) = a, b
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dy = by - ay
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dx = bx - ax
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r = Rational(dy, dx)
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dy = r.numerator
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dx = r.denominator
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y, x = a
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loop do
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break unless input.has_key?([y,x])
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yield [y,x]
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y -= dy
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x -= dx
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end
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y, x = b
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loop do
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break unless input.has_key?([y,x])
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yield [y,x]
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y += dy
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x += dx
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end
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end
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pp freqs.flat_map {|freq|
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antennae = input.select { _2 == freq }.keys
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antennae.combination(2).flat_map {|a,b|
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antinodes(input, a, b).to_a
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}
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}.sort.uniq.length
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__END__
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............
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........0...
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.....0......
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.......0....
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....0.......
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......A.....
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............
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............
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........A...
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.........A..
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............
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............
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