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advent-of-code/2019/ruby/day_03.rb

26 lines
735 B

# typed: false
wire_paths = ARGF.read.lines.map {|l|
l.split(?,).map {|i| [i[0], i[1..-1].to_i] }
}
wire_points = wire_paths.map {|path|
path.each.with_object([[0, 0]]) {|(dir, length), points|
x, y = points.last
length.times {|i|
points << case dir
when ?R then [x+i+1, y]
when ?U then [x, y+i+1]
when ?L then [x-i-1, y]
when ?D then [x, y-i-1]
end
}
}.map.with_index.to_h
}
intersections = wire_points[0].select {|k, _| wire_points[1].has_key?(k) }
intersections.delete([0, 0])
# distances = intersections.map {|(x, y), _| x.abs + y.abs }
distances = intersections.map {|p, d| d + wire_points[1].fetch(p) }
puts distances.min