advent 2019 day 10

10.rb

require 'set'
class Ug
  def foo(input)
    astroids = Set.new
    input.lines.map(&:chomp).each_with_index do |line, x|
      line.chars.each_with_index do |char, y|
        astroids << [y,x] if char == "#"
      end
    end
    counts = {}
    astroids.each_with_index do |station, idx|
      puts "#{idx} / #{astroids.count}"
      sights = (astroids - [station]).find_all do |candidate|
        ((astroids - [station]) - [candidate]).none? do |blocker|
          is_blocked = is_blocked?(station, candidate, blocker)
          is_blocked
        end
      end
      #puts "#{station}: #{sights}"
      counts[station] = sights.count
    end
    puts counts.sort_by(&:last).to_h.inspect
  end

  def is_blocked?(station, candidate, blocker)
    return false if station == blocker
    return false if candidate == blocker
    station_to_blocker = dist(station.first, station.last, blocker.first, blocker.last)
    blocker_to_candidate = dist(blocker.first, blocker.last, candidate.first, candidate.last)
    is_blocked = dist(station.first, station.last, candidate.first, candidate.last).round(5) == (station_to_blocker + blocker_to_candidate).round(5)
  end

  def slope(xa, ya, xb, yb)
    (yb.to_f - ya.to_f) / (xb.to_f - xa.to_f)
  rescue ZeroDivisionError
    -Float::INFINITY
  end

  def dist(xa, ya, xb, yb)
    ((xb - xa)**2 + (yb - ya)**2) ** 0.5
  end

  Astroid = Struct.new(:x, :y, :slope, :dist)

  def do_it_better(input, station)
    station = Astroid.new(station.first, station.last, nil, nil)
    astroids = Set.new
    input.lines.map(&:chomp).each_with_index do |line, y|
      line.chars.each_with_index do |char, x|
        astroids << Astroid.new(x, y, slope(station.x, station.y, x, y), dist(station.x, station.y, x, y)) if char == "#"
      end
    end
    astroids.reject!{|ast| ast.x == station.x && ast.y == station.y}
    max_x = astroids.max_by(&:x)
    max_y = astroids.max_by(&:y)

    vaporized_count =  0
    top_right = astroids.find_all {|ast| ast.x >= station.x && ast.y <= station.y}
    bottom_right = astroids.find_all {|ast| ast.x >= station.x && ast.y > station.y}
    bottom_left = astroids.find_all {|ast| ast.x < station.x && ast.y > station.y}
    top_left = astroids.find_all {|ast| ast.x < station.x && ast.y <= station.y}
    puts top_right.group_by(&:slope).sort_by(&:first).map{|s,opts| opts.min_by(&:dist)}#.map{|slope, opts| opts.sort_by(&:dist)}
    puts bottom_right.group_by(&:slope).sort_by(&:first).map{|s,opts| opts.min_by(&:dist)}#.map{|slope, opts| opts.sort_by(&:dist)}
    puts bottom_left.group_by(&:slope).sort_by(&:first).map{|s,opts| opts.min_by(&:dist)}#.map{|slope, opts| opts.sort_by(&:dist)}
    puts top_left.group_by(&:slope).sort_by(&:first).map{|s,opts| opts.min_by(&:dist)}#.map{|slope, opts| opts.sort_by(&:dist)}
    

  end
  def depricated
    #ug, just convert to polar coord
    while true
      puts "ROTATION"
      exit if vaporized_count > 210
      last_angle = nil
      #first 1/8th
      (station.first.upto(max_x)).each do |x|
        (0.upto(station.last)).each do |y|
          puts "Checking #{[x, y].inspect}"
          next unless astroids.include?([x,y])
          puts "it's an astroid"
          slope = slope(station.first, station.last, x, y) 
          if slope != :it_s_cool
            if slope > -1
              next
            end
          end
          puts "it's in the zone"
          next if astroids.any? do |blocker|
            is_blocked?(station, [x,y], blocker)
          end
          next if last_angle == slope
          last_angle = slope
          vaporized_count += 1
          puts "BAM #{vaporized_count}:#{slope} : #{[x,y].inspect}"
          astroids.delete([x,y])
        end
      end
      # next quarter
      (0.upto(max_y)).each do |y|
        (max_x.downto(station.first)).each do |x|
          next unless astroids.include?([x,y])
          slope = slope(station.first, station.last, x, y) 
          next if slope > 1
          next if astroids.any? do |blocker|
            is_blocked?(station, [x,y], blocker)
          end
          next if last_angle == slope
          last_angle = slope
          vaporized_count += 1
          puts "#{vaporized_count}:#{slope} : #{[x,y].inspect}"
          astroids.delete([x,y])
        end
      end
      # next (bottom) quarter
      (max_x.downto(station.first)).each do |x|
        (max_y.downto(0)).each do |y|
          next unless astroids.include?([x,y])
          slope = slope(station.first, station.last, x, y) 
          if slope != :it_s_cool
            if slope > -1
              next
            end
          end
          next if astroids.any? do |blocker|
            is_blocked?(station, [x,y], blocker)
          end
          next if last_angle == slope
          last_angle = slope
          vaporized_count += 1
          puts "#{vaporized_count}:#{slope} : #{[x,y].inspect}"
          astroids.delete([x,y])
        end
      end
      # next (left) quarter
      (0.upto(station.first)).each do |x|
        (max_y.downto(0)).each do |y|
          next unless astroids.include?([x,y])
          slope = slope(station.first, station.last, x, y) 
          next if slope > -1
          next if astroids.any? do |blocker|
            is_blocked?(station, [x,y], blocker)
          end
          next if last_angle == slope
          last_angle = slope
          vaporized_count += 1
          puts "#{vaporized_count}:#{slope} : #{[x,y].inspect}"
          astroids.delete([x,y])
        end
      end
      # last 8th 
      (0.upto(station.last)).each do |y|
        (0.upto(station.first)).each do |x|
          next unless astroids.include?([x,y])
          slope = slope(station.first, station.last, x, y) 
          next if slope > -1
          next if astroids.any? do |blocker|
            is_blocked?(station, [x,y], blocker)
          end
          next if last_angle == slope
          last_angle = slope
          vaporized_count += 1
          puts "#{vaporized_count}:#{slope} : #{[x,y].inspect}"
          astroids.delete([x,y])
        end
      end
    end
  end
end

#Ug.new.foo(ARGF.read)
Ug.new.do_it_better(ARGF.read, [26, 29])
#Ug.new.do_it_better(ARGF.read, [11, 13])

10_demo.txt

.#..#
.....
#####
....#
...##

10_demo_2.txt

......#.#.
#..#.#....
..#######.
.#.#.###..
.#..#.....
..#....#.#
#..#....#.
.##.#..###
##...#..#.
.#....####

10_demo_3.txt

#.#...#.#.
.###....#.
.#....#...
##.#.#.#.#
....#.#.#.
.##..###.#
..#...##..
..##....##
......#...
.####.###.

10_demo_4.txt

.#..##.###...#######
##.############..##.
.#.######.########.#
.###.#######.####.#.
#####.##.#.##.###.##
..#####..#.#########
####################
#.####....###.#.#.##
##.#################
#####.##.###..####..
..######..##.#######
####.##.####...##..#
.#####..#.######.###
##...#.##########...
#.##########.#######
.####.#.###.###.#.##
....##.##.###..#####
.#.#.###########.###
#.#.#.#####.####.###
###.##.####.##.#..##

10_input.txt

#.....#...#.........###.#........#..
....#......###..#.#.###....#......##
......#..###.......#.#.#.#..#.......
......#......#.#....#.##....##.#.#.#
...###.#.#.......#..#...............
....##...#..#....##....#...#.#......
..##...#.###.....##....#.#..##.##...
..##....#.#......#.#...#.#...#.#....
.#.##..##......##..#...#.....##...##
.......##.....#.....##..#..#..#.....
..#..#...#......#..##...#.#...#...##
......##.##.#.#.###....#.#..#......#
#..#.#...#.....#...#...####.#..#...#
...##...##.#..#.....####.#....##....
.#....###.#...#....#..#......#......
.##.#.#...#....##......#.....##...##
.....#....###...#.....#....#........
...#...#....##..#.#......#.#.#......
.#..###............#.#..#...####.##.
.#.###..#.....#......#..###....##..#
#......#.#.#.#.#.#...#.#.#....##....
.#.....#.....#...##.#......#.#...#..
...##..###.........##.........#.....
..#.#..#.#...#.....#.....#...###.#..
.#..........#.......#....#..........
...##..#..#...#..#...#......####....
.#..#...##.##..##..###......#.......
.##.....#.......#..#...#..#.......#.
#.#.#..#..##..#..............#....##
..#....##......##.....#...#...##....
.##..##..#.#..#.................####
##.......#..#.#..##..#...#..........
#..##...#.##.#.#.........#..#..#....
.....#...#...#.#......#....#........
....#......###.#..#......##.....#..#
#..#...##.........#.....##.....#....