Ruby

[email protected]

https://github.com/snowe2010/advent-of-code/blob/master/ruby_aoc/2023/day07/day07.rb

Gonna clean it up now, but pretty simple at the end of it all. Helps that ruby has several methods to make this dead simple, like tally, any?, all?, and zip

Cleaned up solution:

def get_score(tally)
  vals = tally.values
  map = {
    ->(x) { x.any?(5) } => 7,
    ->(x) { x.any?(4) } => 6,
    ->(x) { x.any?(3) && x.any?(2) } => 5,
    ->(x) { x.any?(3) && tally.all? { |_, v| v != 2 } } => 4,
    ->(x) { x.count(2) == 2 } => 3,
    ->(x) { x.one?(2) && tally.all? { |_, v| v <= 2 } } => 2,
    ->(x) { x.all?(1) } => 1,
  }
  map.find { |lambda, _| lambda.call(vals) }[1]
end

def get_ranking(lines, score_map, scores)
  lines.zip(scores).to_h.sort do |a, b|
    a_line, a_score = a
    b_line, b_score = b
    if a_score == b_score
      a_hand, _ = a_line.split
      b_hand, _ = b_line.split
      diff = a_hand.chars.zip(b_hand.chars).drop_while { |a, b| a == b }[0]
      card_1 = score_map.index(diff[0])
      card_2 = score_map.index(diff[1])
      card_1 <=> card_2
    else
      a_score <=> b_score
    end
  end
end

def calculate_total_winnings(ranking)
  max_rank = ranking.size
  (1..max_rank).sum(0) do |rank|
    line = ranking[rank - 1]
    _, bid = line[0].split
    bid.to_i * rank
  end
end

score_map_p1 = %w[. . 2 3 4 5 6 7 8 9 T J Q K A]
score_map_p2 = %w[. . J 2 3 4 5 6 7 8 9 T Q K A]

execute(1) do |lines|
  scores = lines.map do |line|
    hand, _ = line.split
    tally = hand.split('').tally
    get_score tally
  end
  ranking = get_ranking(lines, score_map_p1, scores)
  calculate_total_winnings ranking
end

execute(2) do |lines|
  scores = lines.map do |line|
    hand, _ = line.split
    hand_split = hand.split('')
    tally = hand_split.tally
    if hand_split.any? { |c| c == 'J' }
      highest_non_j = tally.reject { |k, v| k == 'J' }.max_by { |k, v| v }
      if highest_non_j.nil?
        tally = { 'A': 5 }
      else
        tally[highest_non_j[0]] += tally['J']
      end
      tally.delete('J')
    end
    get_score tally
  end
  ranking = get_ranking(lines, score_map_p2, scores)
  calculate_total_winnings(ranking)
end