40 lines
982 B
PHP
40 lines
982 B
PHP
<?php
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namespace trizz\AdventOfCode\Y21;
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use trizz\AdventOfCode\Solution;
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final class Day3 extends Solution
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{
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public static null|int|string $part1ExampleResult = 198;
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public static null|int|string $part1Result = 3_309_596;
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#[\Override]
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public function part1(array $data): int
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{
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$bits = [];
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foreach ($data as $binary) {
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$split = str_split($binary);
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foreach ($split as $position => $value) {
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$bits[$position][] = $value;
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}
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}
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$gammaRate = '';
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$epsilonRate = '';
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foreach ($bits as $bit) {
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$zeros = array_filter($bit, static fn ($value): bool => $value === '0');
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$ones = array_filter($bit, static fn ($value): bool => $value === '1');
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$gammaRate .= ($ones > $zeros) ? '1' : '0';
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$epsilonRate .= ($ones < $zeros) ? '1' : '0';
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}
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return (int) (bindec($gammaRate) * bindec($epsilonRate));
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}
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}
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