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53 lines
1.7 KiB
53 lines
1.7 KiB
12 months ago
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require "matrix"
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require "set"
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scanners = ARGF.read.strip.split("\n\n").to_h {|scanner|
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id, *rest = scanner.split("\n")
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id = id.scan(/\d+/)[0].to_i
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coords = rest.map { _1.split(?,).map(&:to_i) }
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[id, coords.map { Matrix.column_vector(_1) }]
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}
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first_scanner = scanners.shift
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origin_beacon = first_scanner[1].first
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origin_beacon = Matrix.column_vector([-618,-824,-621])
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known_scanners = {
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first_scanner[0] => [ origin_beacon.map { -_1 }, Matrix.identity(3) ],
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}
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known_beacons = Set.new(first_scanner[1].map {|beacon| beacon - origin_beacon })
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rot_x = Matrix[ [1, 0, 0], [0, 0, -1], [0, 1, 0] ]
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rot_y = Matrix[ [0, 0, 1], [0, 1, 0], [-1, 0, 0] ]
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rot_z = Matrix[ [0, -1, 0], [1, 0, 0], [0, 0, 1] ]
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id = Matrix.identity(3)
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ROTATIONS = Set.new(
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Array.new(4) { rot_x ** _1 }.flat_map {|x|
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Array.new(4) { rot_y ** _1 }.flat_map {|y|
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Array.new(4) { rot_z ** _1 }.map {|z| x * y * z }}}
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)
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def find_overlapping_scanner(known_beacons, scanners)
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scanners.filter_map {|id, beacons|
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haystack = ROTATIONS.flat_map {|r| beacons.map {|b| [ r*b, r ] }}
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# haystack.select { _2 == Matrix.identity(3) }.map(&:first).each { p _1 }
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haystack.find {|position, rotation|
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translated_beacons = beacons.map { (rotation * _1) - position }
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(known_beacons & translated_beacons).size >= 12
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}&.then {|p,o| [id, p, o] }
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}.first
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end
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until scanners.empty?
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id, position, orientation = find_overlapping_scanner(known_beacons, scanners)
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p [id, position, orientation]
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known_scanners[id] = [position, orientation]
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translated_beacons = scanners[id].map {|b| b.zip(position).map { _2 - _1 }.zip(orientation).map { _1 * _2 }}
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known_beacons.merge(translated_beacons)
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scanners.delete(id)
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end
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