Finished day 7, part 1!

src/advent/day7.rb

@@ -0,0 +1,166 @@
+# frozen_string_literal: true
+
+module HandTypeName
+  FIVE_OF_A_KIND = 7
+  FOUR_OF_A_KIND = 6
+  FULL_HOUSE = 5
+  THREE_OF_A_KIND = 4
+  TWO_PAIR = 3
+  ONE_PAIR = 2
+  HIGH_CARD = 1
+
+end
+
+class HandType
+  def initialize(type_name, card_value)
+    @type_name = type_name
+    @card_value = card_value.split("").sort.join("")
+  end
+
+  def ==(o)
+    o.class == self.class && o.type_name == @type_name && o.card_value == @card_value
+  end
+
+  def <=>(o)
+    @type_name <=> o.type_name
+  end
+
+  attr_accessor :type_name
+  attr_accessor :card_value
+end
+
+
+def compare_card(card1, card2)
+  ordered_cards = "AKQJT98765432".reverse
+  if !ordered_cards.include?(card1) || !ordered_cards.include?(card2)
+    raise Exception.new("Unknown card #{card1} or #{card2}")
+  end
+  ordered_cards.index(card1) <=> ordered_cards.index(card2)
+end
+
+class Hand
+  def initialize(cards, bid)
+    @cards = cards
+    @bid = bid
+  end
+
+  def _card_map
+    card_map = {}
+    @cards.each_char do |card|
+      if card_map.include? card
+        card_map[card] += 1
+      else
+        card_map[card] = 1
+      end
+    end
+    card_map
+  end
+
+  def _reversed_card_map
+    ret = {}
+    _card_map.each_pair do |key, value|
+      if ret.include? value
+        ret[value].append key
+      else
+        ret[value] = [key]
+      end
+    end
+    ret
+  end
+
+  def _get_five_of_a_kind
+    if _card_map.values.include? 5
+      return HandType.new HandTypeName::FIVE_OF_A_KIND, _reversed_card_map[5][0]
+    end
+    nil
+  end
+
+  def _get_four_of_a_kind
+    if _card_map.values.include? 4
+      return HandType.new HandTypeName::FOUR_OF_A_KIND, _reversed_card_map[4][0]
+    end
+    nil
+  end
+
+  def _get_full_house
+    if _card_map.values.include?(3) && _card_map.values.include?(2)
+      return HandType.new HandTypeName::FULL_HOUSE, _reversed_card_map[3][0] + _reversed_card_map[2][0]
+    end
+    nil
+  end
+
+  def _get_three_of_a_kind
+    if _card_map.values.include?(3)
+      return HandType.new HandTypeName::THREE_OF_A_KIND, _reversed_card_map[3][0]
+    end
+    nil
+  end
+
+  def _get_two_pairs
+    if _card_map.values.include?(2) && (_reversed_card_map[2].length == 2)
+      return HandType.new HandTypeName::TWO_PAIR, _reversed_card_map[2][0] +  _reversed_card_map[2][1]
+    end
+    nil
+  end
+
+  def _get_one_pair
+    if _card_map.values.include?(2)
+      return HandType.new HandTypeName::ONE_PAIR, _reversed_card_map[2][0]
+    end
+    nil
+  end
+
+  def _get_high_card
+    high_card = @cards.split("").sort {|c1, c2| compare_card(c1, c2)} .last
+    HandType.new HandTypeName::HIGH_CARD, high_card
+  end
+
+  def get_type
+    (_get_five_of_a_kind or
+     _get_four_of_a_kind or
+     _get_full_house or
+     _get_three_of_a_kind or
+     _get_two_pairs or
+     _get_one_pair or
+      _get_high_card)
+  end
+
+  def <=>(other)
+    if (get_type <=> other.get_type) != 0
+      return get_type <=> other.get_type
+    end
+    ((0...5).map {|i| compare_card(@cards[i], other.cards[i])}.drop_while { |v| v == 0}.first) or 0
+  end
+
+  def self.deserialize(line)
+    parts = line.split(/\s+/)
+    self.new parts[0], parts[1].to_i
+
+  end
+
+
+  attr_accessor :cards
+  attr_accessor :bid
+end
+
+
+def play_part_1_game(input)
+  input.strip.split("\n")
+       .filter {|line| !line.empty?}
+       .map {|line| Hand.deserialize line}
+       .sort
+       .each_with_index
+       .map {|hand, idx| hand.bid * (idx + 1)}
+       .reduce 0, :+
+end
+
+
+
+if __FILE__ == $0
+  input_file_name = File.join(File.dirname(__FILE__), "day_7_input.txt")
+  input_content = File.open(input_file_name).read
+
+  puts "Solution to part 1: #{play_part_1_game input_content}"
+
+end
+