78 lines
1.8 KiB
PHP
78 lines
1.8 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 Day2 extends Solution
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{
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public static null|int|string $part1ExampleResult = 150;
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public static null|int|string $part1Result = 1_654_760;
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public static null|int|string $part2ExampleResult = 900;
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public static null|int|string $part2Result = 1_956_047_400;
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#[\Override]
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public function part1(array $data): int
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{
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$depth = 0;
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$horizontal = 0;
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foreach ($data as $current) {
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/**
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* @var string $direction
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* @var int $distance
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*/
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[$direction, $distance] = explode(' ', $current);
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match ($direction) {
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'forward' => $horizontal += $distance,
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'down' => $depth += $distance,
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'up' => $depth -= $distance,
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default => null,
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};
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}
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return $depth * $horizontal;
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}
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#[\Override]
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public function part2(array $data): int
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{
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$aim = 0;
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$depth = 0;
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$horizontal = 0;
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foreach ($data as $current) {
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/**
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* @var string $direction
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* @var int $distance
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*/
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[$direction, $distance] = explode(' ', $current);
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// Can't use 'match' here because of the multiple expressions for 'forward'.
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switch ($direction) {
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case 'forward':
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$horizontal += $distance;
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$depth += $distance * $aim;
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break;
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case 'down':
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$aim += $distance;
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break;
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case 'up':
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$aim -= $distance;
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break;
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}
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}
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return $horizontal * $depth;
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}
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}
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