adventofcode-2022-day-24-part-2-animated-visualization.rb

# https://www.youtube.com/watch?v=vz1oG-YlvAY
# https://www.reddit.com/r/adventofcode/comments/zu3pat/2022_day_24_part_2_terminal_visualization/?utm_source=share&utm_medium=web2x&context=3

require 'paint'
lines = $stdin.readlines.map(&:chomp)
directions = {
  '^' => [0, -1],
  'v' => [0, 1],
  '<' => [-1, 0],
  '>' => [1, 0]
}
directions_inv = directions.invert
width = lines[0].length - 2
height = lines.length - 2
blizzards = []
Blizzard = Struct.new(:x, :y, :direction)
lines.each_with_index do |line, i|
  line.chomp.chars.each_with_index do |char, j|
    x, y = j - 1, i - 1
    if i > 0 && i < lines.length - 1 && j > 0 && j < line.length - 1
      if directions[char]
        blizzards << Blizzard.new(x, y, directions[char])
      end
    end
  end
end
cache = {}
blizzards_at = -> t {
  cache[t] ||= begin
    blizzards.map do |blizzard|
      x, y = blizzard.x + blizzard.direction[0] * t, blizzard.y + blizzard.direction[1] * t
      x %= width
      y %= height
      Blizzard.new(x, y, blizzard.direction)
    end.group_by { |b| [b.x, b.y] }
  end
}
100.times {puts}
draw = -> m, actors = [] {
  out = ""
  groups = actors.group_by(&:pos)
  (-1..height).each do |y|
    (-1..width).each do |x|
      wall = (x == -1 || x == width || y == -1 || y == height) && [x, y] != [0, -1] && [x, y] != [width - 1, height]
      if wall
        out << Paint[' ', :white, :white]
      else
        bs = m[[x, y]]
        if !bs
          if groups[[x, y]]
            max_state = groups[[x, y]].map(&:state).max
            out << Paint[' ', :white, max_state >= 2 ? :green : max_state == 1 ? :blue : :red]
          else
            out << '.'
          end
        elsif bs.length == 1
          out << directions_inv[bs[0].direction]
        elsif bs.length < 10
          out << "#{bs.length}"
        else
          out << 'X'
        end
      end
    end
    out << "\n"
  end
  puts out
}

$start = start = [0, -1]
$goal = goal = [width - 1, height]
$width = width
$height = height
$hypot = Math.hypot(width, height).floor
State = Struct.new(:pos, :t, :state) do
  def finished?
    pos == $goal && state >= 2
  end
  def target
    if state == 1
      $start
    else
      $goal
    end
  end
  def heuristic
    target = self.target
    d = t + (pos[0] - target[0]).abs + (pos[1] - target[1]).abs
    if state == 0
      d += $hypot * 2
    elsif state == 1
      d += $hypot
    end
    d
  end
  def get_next_state_value(new_pos)
    if new_pos == target
      state + 1
    else
      state
    end
  end
end

states = [State.new(start, 0, 0)]
print "\033[1;1H"
p [states.first.t, states.length]
draw[blizzards_at[0], states]
sleep 5
start_time = Time.now

while true
  next_states = []
  added = {}
  states.each do |state|
    if state.finished?
      puts state
      exit
    end
    try_go = -> dx, dy {
      new_x, new_y = state.pos[0] + dx, state.pos[1] + dy
      new_t = state.t + 1
      new_pos = [new_x, new_y]
      new_state = state.get_next_state_value(new_pos)
      key = [new_x, new_y, new_t, new_state]
      if new_pos == goal || new_pos == start || (new_x >= 0 && new_x < width && new_y >= 0 && new_y < height && !blizzards_at[new_t][new_pos])
        if !added[key]
          added[key] = true
          next_states << State.new(new_pos, new_t, new_state)
        end
      end
    }
    try_go[0, -1]
    try_go[0, 1]
    try_go[-1, 0]
    try_go[1, 0]
    try_go[0, 0]
  end
  next_states.sort_by!(&:heuristic)
  next_states = next_states[0..100]
  print "\033[1;1H"
  p [next_states.first.t, next_states.length]
  draw[blizzards_at[next_states.first.t], next_states]
  states = next_states
  sleep 0.033
end