Refactor framework to support more years

src/Y21/Day6.php

@@ -0,0 +1,92 @@
+<?php
+
+namespace trizz\AdventOfCode\Y21;
+
+use trizz\AdventOfCode\Solution;
+use JetBrains\PhpStorm\Immutable;
+
+class Day6 extends Solution
+{
+    public static int|string|null $part1ExampleResult = 5934;
+    public static int|string|null $part1Result = 350917;
+
+    public static int|string|null $part2ExampleResult = 26984457539;
+    public static int|string|null $part2Result = 1592918715629;
+
+    /**
+     * @var int[]
+     * @psalm-param array{int: int}
+     */
+    #[Immutable]
+    protected array $startState = [
+        8 => 0,
+        7 => 0,
+        6 => 0,
+        5 => 0,
+        4 => 0,
+        3 => 0,
+        2 => 0,
+        1 => 0,
+        0 => 0,
+    ];
+
+    /**
+     * {@inheritdoc}
+     */
+    public function part1(array $data): int
+    {
+        return $this->processPuzzle(80, $data[0]);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function part2(array $data): int
+    {
+        return $this->processPuzzle(256, $data[0]);
+    }
+
+    /**
+     * @param int[] $state
+     * @psalm-param array{int: int} $state
+     *
+     * @return array
+     */
+    protected function processDay(array $state): array
+    {
+        $newState = $state;
+
+        /**
+         * @var int $key
+         * @var int $stateValue
+         */
+        foreach ($state as $key => $stateValue) {
+            $newKey = $key - 1;
+
+            if ($newKey < 0) {
+                $newState[8] = $stateValue;
+                $newKey = 6;
+            }
+
+            $newState[$key] -= $stateValue;
+            $newState[$newKey] += $stateValue;
+        }
+
+        return $newState;
+    }
+
+    protected function processPuzzle(int $numberOfDays, string $data): int
+    {
+        $state = $this->startState;
+
+        array_map(static function (string $stateValue) use (&$state) {
+            ++$state[(int) $stateValue];
+        }, explode(',', $data));
+
+        for ($day = 0; $day < $numberOfDays; ++$day) {
+            $state = $this->processDay($state);
+        }
+
+        return (int) array_sum($state);
+    }
+}