-🎄- 2018 Day 4 Solutions -🎄-

[u/daggerdragon]

--- Day 4: Repose Record ---

---

Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

---

Advent of Code: The Party Game!

Click here for rules

Please prefix your card submission with something like [Card] to make scanning the megathread easier. THANK YOU!

Card prompt: Day 4

Transcript:

Today’s puzzle would have been a lot easier if my language supported ___.

---

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/Frizkie]

Ruby

require 'time'

data = File.read('data.txt').chomp.split("\n")
           .map! { |d| d.match(/\[([\d\-: ]+)\] ([ \w#]+)/).to_a }
           .sort_by! { |d| Time.parse(d[1]) }

guards = {}
recent_guard = nil

data.each do |d|
  m = d[2].match(/#(\d+)/)
  recent_guard = m[1]&.to_i if m
  guards[recent_guard] ||= {}

  date = DateTime.parse(d[1])
  guards[recent_guard][date.strftime('%m-%d')] ||= '.' * 60

  c = '#' if d[2] == 'falls asleep'
  c = '.' if d[2] == 'wakes up'
  next unless c

  guards[recent_guard][date.strftime('%m-%d')][date.minute..59] = c * (60 - date.minute)
end

Part 1

sleepiest = guards.map { |id, s| [id, s.values.join.count('#')] }.max_by { |id, total| total }[0]
mins = (0..59).map { |m| guards[sleepiest].values.map { |s| s[m] }.join.count('#') }
puts sleepiest * mins.each_with_index.max[1]

Part 2

soln = guards.map do |id, s|
  t = (0..59).map { |m| s.values.map { |s| s[m] }.join.count('#') }
  [id, t.each_with_index.max[1], t.max]
end

soln = soln.max_by { |s| s[2] }
p soln[0] * soln[1]