24 lines
531 B
PHP
24 lines
531 B
PHP
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<?php
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$input = file_get_contents('input.txt');
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[$earliest_timestamp, $buses] = explode("\n", $input);
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$earliest_timestamp = (int) $earliest_timestamp;
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$buses = array_filter(
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array_map(static function ($bus) {
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return $bus === 'x' ? null : (int) $bus;
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}, explode(',', $buses))
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);
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$timestamp = $earliest_timestamp;
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while (true) {
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foreach ($buses as $bus) {
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if ($timestamp % $bus === 0) {
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echo ($timestamp - $earliest_timestamp) * $bus;
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exit;
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}
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}
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$timestamp++;
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}
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