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34 lines
874 B
34 lines
874 B
DIMENSIONS = 4
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state = ARGF.read.strip.split("\n").flat_map.with_index {|line,y|
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line.chars.map.with_index {|c,x|
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[[x,y].fill(0, 2, DIMENSIONS-2), c == "#"]
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}
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}.to_h
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NEIGHBORS = (0...3**DIMENSIONS)
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.reject {|n| n == 3**DIMENSIONS / 2 }
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.map {|n| n.digits(3) }
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.map {|n| (0...DIMENSIONS).map {|x| n.fetch(x, 0) - 1 }}
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def tick(state)
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actives = state.select {|_,c| c }.keys
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minmaxes = actives
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.transpose.map(&:minmax)
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.map {|min,max| (min-1..max+1).to_a }
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coords = minmaxes.inject {|n,x|
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n.flat_map {|nn| x.map {|xx| [nn, xx] }}
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}.map(&:flatten)
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coords.map {|coord|
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active_neighbors = NEIGHBORS.count {|delta| state[coord.zip(delta).map {|a,b| a + b }] }
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[ coord,
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state[coord] ? (2..3).cover?(active_neighbors) : active_neighbors == 3
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]
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}.to_h
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end
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6.times do
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state = tick(state)
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end
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p state.values.count(&:itself)
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