2024 Day 01 part 1 & 2 (#26)

- Updates to dependencies.
- Add PHP 8.4 to test matrix.
- Remove PHP 8.1 from test matrix.

.github/workflows/tests.yml

@@ -12,9 +12,9 @@ jobs:
 
     strategy:
       matrix:
-        php: [ 8.1, 8.2, 8.3 ]
+        php: [ 8.2, 8.3, 8.4 ]
         os: [ ubuntu-latest ]
-        year: [ 2015, 2018, 2019, 2020, 2021, 2022, 2023 ]
+        year: [ 2015, 2018, 2019, 2020, 2021, 2022, 2023, 2024 ]
 
     name: PHP ${{ matrix.php }} - Unit Tests for Year ${{ matrix.year }}
 

2024/day-01.php

@@ -0,0 +1,120 @@
+<?php
+
+require __DIR__ . '/../vendor/autoload.php';
+
+use adventofcode\Year2024\ShortestDistanceParser;
+
+/**
+ * --- Day 1: Historian Hysteria ---
+ *
+ * The Chief Historian is always present for the big Christmas sleigh launch, but nobody has seen him in months! Last
+ * anyone heard, he was visiting locations that are historically significant to the North Pole; a group of Senior
+ * Historians has asked you to accompany them as they check the places they think he was most likely to visit.
+ *
+ * As each location is checked, they will mark it on their list with a star. They figure the Chief Historian must be in
+ * one of the first fifty places they'll look, so in order to save Christmas, you need to help them get fifty stars on
+ * their list before Santa takes off on December 25th.
+ *
+ * Collect stars by solving puzzles. Two puzzles will be made available on each day in the Advent calendar; the second
+ * puzzle is unlocked when you complete the first. Each puzzle grants one star. Good luck!
+ *
+ * You haven't even left yet and the group of Elvish Senior Historians has already hit a problem: their list of
+ * locations to check is currently empty. Eventually, someone decides that the best place to check first would be the
+ * Chief Historian's office.
+ *
+ * Upon pouring into the office, everyone confirms that the Chief Historian is indeed nowhere to be found. Instead, the
+ * Elves discover an assortment of notes and lists of historically significant locations! This seems to be the planning
+ * the Chief Historian was doing before he left. Perhaps these notes can be used to determine which locations to search?
+ *
+ * Throughout the Chief's office, the historically significant locations are listed not by name but by a unique number
+ * called the location ID. To make sure they don't miss anything, The Historians split into two groups, each searching
+ * the office and trying to create their own complete list of location IDs.
+ *
+ * There's just one problem: by holding the two lists up side by side (your puzzle input), it quickly becomes clear that
+ * the lists aren't very similar. Maybe you can help The Historians reconcile their lists?
+ *
+ * For example:
+ *
+ * 3   4
+ * 4   3
+ * 2   5
+ * 1   3
+ * 3   9
+ * 3   3
+ *
+ * Maybe the lists are only off by a small amount! To find out, pair up the numbers and measure how far apart they are.
+ * Pair up the smallest number in the left list with the smallest number in the right list, then the second-smallest
+ * left number with the second-smallest right number, and so on.
+ *
+ * Within each pair, figure out how far apart the two numbers are; you'll need to add up all of those distances. For
+ * example, if you pair up a 3 from the left list with a 7 from the right list, the distance apart is 4; if you pair
+ * up a 9 with a 3, the distance apart is 6.
+ *
+ * In the example list above, the pairs and distances would be as follows:
+ *
+ *   - The smallest number in the left list is 1, and the smallest number in the right list is 3.
+ *     The distance between them is 2.
+ *   - The second-smallest number in the left list is 2, and the second-smallest number in the right list is another 3.
+ *     The distance between them is 1.
+ *   - The third-smallest number in both lists is 3, so the distance between them is 0.
+ *   - The next numbers to pair up are 3 and 4, a distance of 1.
+ *   - The fifth-smallest numbers in each list are 3 and 5, a distance of 2.
+ *   - Finally, the largest number in the left list is 4, while the largest number in the right list is 9;
+ *     these are a distance 5 apart.
+ *
+ * To find the total distance between the left list and the right list, add up the distances between all of the pairs
+ * you found. In the example above, this is 2 + 1 + 0 + 1 + 2 + 5, a total distance of 11!
+ *
+ * Your actual left and right lists contain many location IDs. What is the total distance between your lists?
+ */
+
+$shortestDistanceParser = new ShortestDistanceParser();
+
+$listValues = file(__DIR__ . '/inputs/day-01.input', FILE_IGNORE_NEW_LINES);
+
+$sum = $shortestDistanceParser->findShortestDistanceSum($listValues);
+print('The sum of the shortest distances values based on the supplied lists is ' . $sum . ".\n");
+
+/**
+ * --- Part Two ---
+ *
+ * Your analysis only confirmed what everyone feared: the two lists of location IDs are indeed very different.
+ *
+ * Or are they?
+ *
+ * The Historians can't agree on which group made the mistakes or how to read most of the Chief's handwriting, but in
+ * the commotion you notice an interesting detail: a lot of location IDs appear in both lists! Maybe the other numbers
+ * aren't location IDs at all but rather misinterpreted handwriting.
+ *
+ * This time, you'll need to figure out exactly how often each number from the left list appears in the right list.
+ * Calculate a total similarity score by adding up each number in the left list after multiplying it by the number of
+ * times that number appears in the right list.
+ *
+ * Here are the same example lists again:
+ *
+ * 3   4
+ * 4   3
+ * 2   5
+ * 1   3
+ * 3   9
+ * 3   3
+ *
+ * For these example lists, here is the process of finding the similarity score:
+ *
+ *   - The first number in the left list is 3. It appears in the right list three times,
+ *     so the similarity score increases by 3 * 3 = 9.
+ *   - The second number in the left list is 4. It appears in the right list once,
+ *     so the similarity score increases by 4 * 1 = 4.
+ *   - The third number in the left list is 2. It does not appear in the right list,
+ *     so the similarity score does not increase (2 * 0 = 0).
+ *   - The fourth number, 1, also does not appear in the right list.
+ *   - The fifth number, 3, appears in the right list three times; the similarity score increases by 9.
+ *   - The last number, 3, appears in the right list three times; the similarity score again increases by 9.
+ *
+ * So, for these example lists, the similarity score at the end of this process is 31 (9 + 4 + 0 + 0 + 9 + 9).
+ *
+ * Once again consider your left and right lists. What is their similarity score?
+ */
+
+$sum = $shortestDistanceParser->findSimilarityScoreSum($listValues);
+print('The sum of the similarity scores based on the supplied lists is ' . $sum . ".\n");

2024/inputs/day-01-sample.input

@@ -0,0 +1,6 @@
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3