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