day 7

examples/07.txt

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+32T3K 765
+T55J5 684
+KK677 28
+KTJJT 220
+QQQJA 483

lib/days/07.rb

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+class Day07
+
+  # LABELS = ['High Card', 'Pair', 'Two Pair', 'Three of a Kind', 'Full House', 'Four of a Kind', 'Five of a Kind']
+  CARD_VALUES = ['2', '3', '4', '5', '6', '7', '8', '9', 'T', 'J', 'Q', 'K', 'A'].freeze
+
+  HandP1 = Struct.new(:cards, :bid) do
+    def hand_value
+      counts = cards.chars.group_by(&:to_s).values.map(&:length)
+
+      if counts == [5]
+        6
+      elsif counts.include?(4)
+        5
+      elsif counts.include?(3) && counts.include?(2)
+        4
+      elsif counts.include?(3)
+        3
+      elsif counts.select { |c| c == 2 }.length == 2
+        2
+      elsif counts.include?(2)
+        1
+      else
+        0
+      end
+    end
+
+    def card_value
+      cards.chars.map { |c| CARD_VALUES.index(c).to_s.rjust(2, '0') }.join
+    end
+
+    def value
+      "#{hand_value}.#{card_value}".to_f
+    end
+  end
+
+  def part1(input)
+    hands = input.split("\n").map do |line|
+      args = line.split.map(&:strip)
+      HandP1.new(args.first, args.last.to_i)
+    end
+
+    hands.sort_by(&:value).each_with_index.map do |h, index|
+      h.bid * (index + 1)
+    end.sum
+  end
+
+  CARD_VALUES_2 = ['J', '2', '3', '4', '5', '6', '7', '8', '9', 'T', 'Q', 'K', 'A'].freeze
+
+  HandP2 = Struct.new(:cards, :bid) do
+    def hand_value
+      jokers = cards.scan('J').length
+      counts = cards.delete('J').chars.group_by(&:to_s).values.map(&:length)
+
+      if counts.length == 1 || jokers == 5 # 5 of a kind
+        6
+      elsif counts.max == 4 || counts.max + jokers == 4 || jokers == 4 # 4 of a kind
+        5
+      elsif (counts.include?(3) && counts.include?(2)) || # full house
+            jokers == 3 ||
+            (jokers == 2 && counts.length == 2) ||
+            (jokers == 1 && counts.length == 2)
+        4
+      elsif counts.max == 3 || jokers == 3 || counts.max + jokers == 3 # 3 of a kind
+        3
+      elsif counts.select { |c| c == 2 }.length == 2 || jokers >= 2 # 2 pair
+        2
+      elsif counts.include?(2) || jokers.positive? # pair
+        1
+      else
+        0
+      end
+    end
+
+    def card_value
+      cards.chars.map do |c|
+        CARD_VALUES_2.index(c).to_s.rjust(2, '0')
+      end.join
+    end
+
+    def value
+      "#{hand_value}.#{card_value}".to_f
+    end
+  end
+
+  def part2(input)
+    hands = input.split("\n").map do |line|
+      args = line.split.map(&:strip)
+      HandP2.new(args.first, args.last.to_i)
+    end
+
+    hands.sort_by(&:value).each_with_index.map do |h, index|
+      h.bid * (index + 1)
+    end.sum
+  end
+
+end

test/07_test.rb

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+require 'minitest/autorun'
+require 'minitest/pride'
+require_relative '../app'
+
+class TestDay07 < Minitest::Test
+  def setup
+    @data = File.read(File.join(APP_ROOT, 'examples', '07.txt')).rstrip
+    @day = Day07.new
+  end
+
+  def test_part1
+    assert_equal @day.part1(@data), 6440
+  end
+
+  def test_part2
+    assert_equal @day.part2(@data), 5905
+  end
+end