12 lines
416 B
PHP
12 lines
416 B
PHP
<?php
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$input = file('input', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
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$input = array_map('str_split', $input);
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$gamma = $epsilon = [];
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for ($i = 0; $i < count($input[0]); $i++) {
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$bit = (int) (array_sum($column = array_column($input, $i)) >= ceil(count($column) / 2));
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$gamma[] = $bit;
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$epsilon[] = ~$bit & 1;
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}
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echo bindec(implode('', $gamma)) * bindec(implode('', $epsilon)).PHP_EOL; //3813416
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