day19.rb

if ARGV.empty?
  data = DATA.readlines(chomp: true)
else
  data = File.readlines(ARGV.first, chomp: true)
end

def blueprints(data)
  data.map do |line|
    match = /Blueprint (?<id>\d+): Each ore robot costs (?<ore_robot_ore>\d+) ore. Each clay robot costs (?<clay_robot_ore>\d+) ore. Each obsidian robot costs (?<obsidian_robot_ore>\d+) ore and (?<obsidian_robot_clay>\d+) clay. Each geode robot costs (?<geode_robot_ore>\d+) ore and (?<geode_robot_obsidian>\d+) obsidian./.match(line)
    {
      id: match[:id].to_i,
      ore_bot_ore: match[:ore_robot_ore].to_i,
      clay_bot_ore: match[:clay_robot_ore].to_i,
      obsidian_bot_ore: match[:obsidian_robot_ore].to_i,
      obsidian_bot_clay: match[:obsidian_robot_clay].to_i,
      geode_bot_ore: match[:geode_robot_ore].to_i,
      geode_bot_obsidian: match[:geode_robot_obsidian].to_i,
      ore_max: [
        match[:ore_robot_ore].to_i,
        match[:clay_robot_ore].to_i,
        match[:obsidian_robot_ore].to_i,
        match[:geode_robot_ore].to_i
      ].max + 1
    }
  end
end

SEEN = {}
def max_geodes(
  blueprint,
  ore_robots,
  clay_robots,
  obsidian_robots,
  geode_robots,
  ore,
  clay,
  obsidian,
  geodes,
  time_left
)
  return geodes if time_left == 0
  key = [
    ore_robots,
    clay_robots,
    obsidian_robots,
    geode_robots,
    ore % blueprint[:ore_max] + 1,
    clay % blueprint[:obsidian_bot_clay] + 1,
    obsidian % blueprint[:geode_bot_obsidian] + 1,
    geodes,
    time_left
  ]
  return SEEN[key] if SEEN.key?(key)

  max = max_geodes(
    blueprint,
    ore_robots,
    clay_robots,
    obsidian_robots,
    geode_robots,
    ore + ore_robots,
    clay + clay_robots,
    obsidian + obsidian_robots,
    geodes + geode_robots,
    time_left - 1
  )

  # Can we buy an ore bot?
  if ore >= blueprint[:ore_bot_ore] &&
      ore_robots <= blueprint[:ore_max]
    option = max_geodes(
      blueprint,
      ore_robots + 1,
      clay_robots,
      obsidian_robots,
      geode_robots,
      ore - blueprint[:ore_bot_ore] + ore_robots,
      clay + clay_robots,
      obsidian + obsidian_robots,
      geodes + geode_robots,
      time_left - 1
    )
    max = option if option > max
  end

  # Can we buy a clay bot?
  if ore >= blueprint[:clay_bot_ore] &&
      clay_robots <= blueprint[:obsidian_bot_clay]
    option = max_geodes(
      blueprint,
      ore_robots,
      clay_robots + 1,
      obsidian_robots,
      geode_robots,
      ore - blueprint[:clay_bot_ore] + ore_robots,
      clay + clay_robots,
      obsidian + obsidian_robots,
      geodes + geode_robots,
      time_left - 1
    )
    max = option if option > max
  end

  # Can we buy an obsidian bot?
  if ore >= blueprint[:obsidian_bot_ore] &&
      clay >= blueprint[:obsidian_bot_clay] &&
      obsidian_robots <= blueprint[:geode_bot_obsidian]
    option = max_geodes(
      blueprint,
      ore_robots,
      clay_robots,
      obsidian_robots + 1,
      geode_robots,
      ore - blueprint[:obsidian_bot_ore] + ore_robots,
      clay - blueprint[:obsidian_bot_clay] + clay_robots,
      obsidian + obsidian_robots,
      geodes + geode_robots,
      time_left - 1
    )
    max = option if option > max
  end

  # Can we buy a geode bot?
  if ore >= blueprint[:geode_bot_ore] &&
      obsidian >= blueprint[:geode_bot_obsidian]
    option = max_geodes(
      blueprint,
      ore_robots,
      clay_robots,
      obsidian_robots,
      geode_robots + 1,
      ore - blueprint[:geode_bot_ore] + ore_robots,
      clay + clay_robots,
      obsidian - blueprint[:geode_bot_obsidian] + obsidian_robots,
      geodes + geode_robots,
      time_left - 1
    )
    max = option if option > max
  end

  SEEN[key] = max
  max
end

# sum = 0
# blueprints(data).each do |blueprint|
#   puts "Blueprint #{blueprint[:id]}"
#   SEEN.clear
#   quality = blueprint[:id] * max_geodes(
#     blueprint,
#     1, 0, 0, 0, 0, 0, 0, 0, 24
#   )
#   sum += quality
# end
# puts sum

prints = blueprints(data).take(3)

product = 1
prints.each do |blueprint|
  puts "Blueprint #{blueprint[:id]}"
  SEEN.clear
  product *= max_geodes(
    blueprint,
    1, 0, 0, 0, 0, 0, 0, 0, 32
  )
end
p product


# p max_geodes(
#   blueprints(data).last, 1, 0, 0, 0, 0, 0, 0, 0, 24
# )

__END__
Blueprint 1: Each ore robot costs 4 ore. Each clay robot costs 2 ore. Each obsidian robot costs 3 ore and 14 clay. Each geode robot costs 2 ore and 7 obsidian.
Blueprint 2: Each ore robot costs 2 ore. Each clay robot costs 3 ore. Each obsidian robot costs 3 ore and 8 clay. Each geode robot costs 3 ore and 12 obsidian.

https://youtu.be/O1EWLebIaAU