ref: Reorganize Day 2 files

Author: cdalvaro

lib/puzzles/2023/day01/README.md

@@ -1,6 +1,6 @@
 # Day 1: Trebuchet?!
 
-## Part 1
+## Part One
 
 Something is wrong with global snow production, and you've been selected to take a look. The Elves have even given you a map; on it, they've used stars to mark the top fifty locations that are likely to be having problems.
 
@@ -29,7 +29,7 @@ Consider your entire calibration document. **What is the sum of all of the calib
 
 Your puzzle answer was `54450`.
 
-## Part 2
+## Part Two
 
 Your calculation isn't quite right. It looks like some of the digits are actually **spelled out with letters**: `one`, `two`, `three`, `four`, `five`, `six`, `seven`, `eight`, and `nine` **also** count as valid "digits".
 

lib/puzzles/2023/day02.rb

@@ -0,0 +1,61 @@
+# Day 2: Cube Conundrum
+
+## Part One
+
+You're launched high into the atmosphere! The apex of your trajectory just barely reaches the surface of a large island floating in the sky. You gently land in a fluffy pile of leaves. It's quite cold, but you don't see much snow. An Elf runs over to greet you.
+
+The Elf explains that you've arrived at **Snow Island** and apologizes for the lack of snow. He'll be happy to explain the situation, but it's a bit of a walk, so you have some time. They don't get many visitors up here; would you like to play a game in the meantime?
+
+As you walk, the Elf shows you a small bag and some cubes which are either red, green, or blue. Each time you play this game, he will hide a secret number of cubes of each color in the bag, and your goal is to figure out information about the number of cubes.
+
+To get information, once a bag has been loaded with cubes, the Elf will reach into the bag, grab a handful of random cubes, show them to you, and then put them back in the bag. He'll do this a few times per game.
+
+You play several games and record the information from each game (your puzzle input). Each game is listed with its ID number (like the `11` in `Game 11: ...`) followed by a semicolon-separated list of subsets of cubes that were revealed from the bag (like `3 red, 5 green, 4 blue`).
+
+For example, the record of a few games might look like this:
+
+```
+Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green
+```
+
+In game 1, three sets of cubes are revealed from the bag (and then put back again). The first set is 3 blue cubes and 4 red cubes; the second set is 1 red cube, 2 green cubes, and 6 blue cubes; the third set is only 2 green cubes.
+
+The Elf would first like to know which games would have been possible if the bag contained **only 12 red cubes, 13 green cubes, and 14 blue cubes**?
+
+In the example above, games 1, 2, and 5 would have been **possible** if the bag had been loaded with that configuration. However, game 3 would have been **impossible** because at one point the Elf showed you 20 red cubes at once; similarly, game 4 would also have been **impossible** because the Elf showed you 15 blue cubes at once. If you add up the IDs of the games that would have been possible, you get **`8`**.
+
+Determine which games would have been possible if the bag had been loaded with only 12 red cubes, 13 green cubes, and 14 blue cubes. **What is the sum of the IDs of those games?**
+
+Your puzzle answer was `2278`.
+
+## Part Two
+
+The Elf says they've stopped producing snow because they aren't getting any **water**! He isn't sure why the water stopped; however, he can show you how to get to the water source to check it out for yourself. It's just up ahead!
+
+As you continue your walk, the Elf poses a second question: in each game you played, what is the **fewest number of cubes of each color** that could have been in the bag to make the game possible?
+
+Again consider the example games from earlier:
+
+```
+Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green
+```
+
+- In game 1, the game could have been played with as few as 4 red, 2 green, and 6 blue cubes. If any color had even one fewer cube, the game would have been impossible.
+- Game 2 could have been played with a minimum of 1 red, 3 green, and 4 blue cubes.
+- Game 3 must have been played with at least 20 red, 13 green, and 6 blue cubes.
+- Game 4 required at least 14 red, 3 green, and 15 blue cubes.
+- Game 5 needed no fewer than 6 red, 3 green, and 2 blue cubes in the bag.
+
+The **power** of a set of cubes is equal to the numbers of red, green, and blue cubes multiplied together. The power of the minimum set of cubes in game 1 is `48`. In games 2-5 it was `12`, `1560`, `630`, and `36`, respectively. Adding up these five powers produces the sum **`2286`**.
+
+For each game, find the minimum set of cubes that must have been present. **What is the sum of the power of these sets?**
+
+Your puzzle answer was `67953`.

lib/puzzles/2023/day02/README.md

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require_relative "part1"
+require_relative "part2"
+
+module AdventOfCode
+  module Puzzles2023
+    ##
+    # Advent of Code 2023 - Day 2
+    # https://adventofcode.com/2023/day/2
+    # {include:file:lib/puzzles/2023/day02/README.md}
+    module Day02
+    end
+  end
+end

lib/puzzles/2023/day02/day02.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module AdventOfCode
+  module Puzzles2023
+    module Day02
+      ##
+      # Game class to store the game id and its sets.
+      class Game
+        ##
+        # @return [Integer] game id
+        attr_reader :id
+
+        ##
+        # @return [Array<Set>] sets of cubes
+        attr_reader :sets
+
+        ##
+        # @param id [Integer] game id
+        # @param sets [Array<Set>] sets of cubes
+        def initialize(id:, sets:)
+          @id = id
+          @sets = sets
+        end
+
+        ##
+        # Check if the game is valid given the number of blue, green,
+        # and red cubes.
+        #
+        # @param blue [Integer] number of blue cubes
+        # @param green [Integer] number of green cubes
+        # @param red [Integer] number of red cubes
+        #
+        # @return [Boolean] true if the game is valid, false otherwise
+        def valid?(blue:, green:, red:)
+          # A game is valid only if every set has the same or less
+          # number of blue, green, and red cubes as the set it is
+          sets.each do |set|
+            return false if set.blue > blue
+            return false if set.green > green
+            return false if set.red > red
+          end
+          true
+        end
+      end
+    end
+  end
+end