93 lines
1.8 KiB
Ruby
93 lines
1.8 KiB
Ruby
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#!/usr/bin/env ruby
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problem = 8
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input = File.readlines("#{problem}.input").map(&:strip)
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#input = DATA.read.split("\n")
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# Find diferent antennas
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signals = input.join.chars.uniq
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.reject { _1 == "." }
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.map { [_1, []] }
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.to_h
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grid = input.map(&:chars)
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# map antenna locations
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signals.keys.each do |signal|
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grid.each_with_index do |row, x|
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row.each_with_index do |val, y|
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signals[val] << [x, y] if val == signal
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end
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end
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end
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# calculate antinodes between all node pairs
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antinodes = []
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signals.each do |(signal, locations)|
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locations.each { antinodes << _1 }
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locations.combination(2).each do |(first, second)|
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x = (first.first - second.first).abs
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y = (first.last - second.last).abs
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node1, node2 = first, second
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loop do
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if first.first < second.first
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x1 = node1.first - x
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else
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x1 = node1.first + x
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end
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if first.last < second.last
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y1 = node1.last - y
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else
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y1 = node1.last + y
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end
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node1 = [x1, y1]
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break unless x1 >= 0 && y1 >= 0 && x1 < grid.size && y1 < grid.first.size
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antinodes << node1
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end
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loop do
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if first.first < second.first
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x2 = node2.first + x
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else
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x2 = node2.first - x
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end
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if first.last < second.last
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y2 = node2.last + y
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else
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y2 = node2.last - y
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end
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node2 = [x2, y2]
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break unless x2 >= 0 && y2 >= 0 && x2 < grid.size && y2 < grid.first.size
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antinodes << node2
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end
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end
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end
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p antinodes.uniq.size
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grid.each_with_index do |row, x|
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row.each_with_index do |val, y|
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if antinodes.index([x,y])
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print "#"
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else
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print grid[x][y]
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end
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end
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puts
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end
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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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