Move solutions out of the source itself

data/Y21/day7/Day7.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace trizz\AdventOfCode\Y21;
+
+use trizz\AdventOfCode\Solution;
+
+final class Day7 extends Solution
+{
+    public static null|int|string $part1ExampleResult = 37;
+
+    public static null|int|string $part1Result = 344297;
+
+    public static null|int|string $part2ExampleResult = 168;
+
+    public static null|int|string $part2Result = 97_164_301;
+
+    #[\Override]
+    public function part1(array $data): int
+    {
+        return $this->calculateFuel($data[0], forPart2: false);
+    }
+
+    #[\Override]
+    public function part2(array $data): int
+    {
+        return $this->calculateFuel($data[0], forPart2: true);
+    }
+
+    private function calculateFuel(string $data, bool $forPart2 = false): int
+    {
+        $crabs = array_map(static fn (string $crab): int => (int) $crab, explode(',', $data));
+
+        /** @var array<int, int> $fuelPerPosition */
+        $fuelPerPosition = [];
+
+        $minCrab = min($crabs);
+        $maxCrab = max($crabs);
+
+        for ($position = $minCrab; $position <= $maxCrab; ++$position) {
+            foreach ($crabs as $crab) {
+                if (!isset($fuelPerPosition[$position])) {
+                    $fuelPerPosition[$position] = 0;
+                }
+
+                $consumption = abs($position - $crab);
+
+                if ($forPart2) {
+                    $consumption = $consumption * ($consumption + 1) / 2;
+                }
+
+                $fuelPerPosition[$position] += $consumption;
+            }
+        }
+
+        return (int) min($fuelPerPosition);
+    }
+}