Add day 4

2023-12-04 17:08:01 +01:00
parent 49a526bce2
commit 5702b333c6
3 changed files with 297 additions and 0 deletions
--- a/data/Y23/day4/Day4.php
+++ b/data/Y23/day4/Day4.php
@ -0,0 +1,89 @@
+<?php
+
+namespace trizz\AdventOfCode\Y23;
+
+final class Day4 extends \trizz\AdventOfCode\Solution
+{
+    public static null|int|string $part1ExampleResult = 13;
+
+    public static null|int|string $part1Result = 24733;
+
+    public static null|int|string $part2ExampleResult = 30;
+
+    public static null|int|string $part2Result = 5_422_730;
+
+    private mixed $scoringNumbersPerCard;
+
+    private int $totalCards;
+
+    private mixed $numberOfCards;
+
+    #[\Override]
+    public function part1(array $data): int
+    {
+        $score = 0;
+        foreach ($data as $line) {
+            [$winningNumbers, $cardNumbers] = $this->parseInput($line);
+            $scoringNumbers = array_intersect($winningNumbers, $cardNumbers);
+
+            if ($scoringNumbers === []) {
+                continue;
+            }
+
+            $cardScore = 1;
+            for ($i = 0; $i < count($scoringNumbers) - 1; ++$i) {
+                $cardScore *= 2;
+            }
+
+            $score += $cardScore;
+        }
+
+        return $score;
+    }
+
+    #[\Override]
+    public function part2(array $data): int
+    {
+        $this->totalCards = count($data);
+        foreach ($data as $card => $line) {
+            [$winningNumbers, $cardNumbers] = $this->parseInput($line);
+            $scoringNumbers = array_intersect($winningNumbers, $cardNumbers);
+            $this->scoringNumbersPerCard[$card] = count($scoringNumbers);
+            $this->numberOfCards[$card] = 1;
+        }
+
+        // Start the recursive loop with the first card.
+        $this->updateCount(0);
+
+        return array_sum($this->numberOfCards);
+    }
+
+    public function updateCount(int $card): void
+    {
+        $cardCount = $this->numberOfCards[$card] ?? 0;
+        for ($i = 0; $i < $cardCount; ++$i) {
+            $winningNumbers = $this->scoringNumbersPerCard[$card] ?? 0;
+            for ($number = 1; $number <= $winningNumbers; ++$number) {
+                ++$this->numberOfCards[$card + $number];
+            }
+        }
+
+        if ($card <= $this->totalCards) {
+            $this->updateCount($card + 1);
+        }
+    }
+
+    /**
+     * @return array<int, array<int>>
+     */
+    public function parseInput(string $input): array
+    {
+        $numbers = explode(':', $input)[1];
+        [$winningNumbers, $cardNumbers] = explode('|', $numbers, 2);
+
+        $winningNumbers = array_map('intval', array_filter(explode(' ', $winningNumbers)));
+        $cardNumbers = array_map('intval', array_filter(explode(' ', $cardNumbers)));
+
+        return [$winningNumbers, $cardNumbers];
+    }
+}