54 lines
1.4 KiB
PHP
54 lines
1.4 KiB
PHP
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<?php
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$operations = explode("\n", file_get_contents('input.txt'));
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$results = [];
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foreach ($operations as $i => $operation) {
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$operation = evaluateParentheses($operation);
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$operation = evaluateOperation($operation);
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$results[] = (int) $operation;
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echo sprintf('Line %u : %u%s', $i+1, $operation, "\n");
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}
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echo array_sum($results);
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/**
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* @param string $operation
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*
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* @return false|float|int
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* @throws \Exception
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*/
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function evaluateOperation(string $operation)
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{
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while (!is_numeric($operation)) {
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$operation = preg_replace_callback(
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'/^(\d+) (\+|\*) (\d+)/',
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static function ($matches) {
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switch ($matches[2]) {
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case '+':
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return (int)$matches[1] + (int)$matches[3];
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case '*':
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return (int)$matches[1] * (int)$matches[3];
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default:
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throw new \Exception('Unknown Operation ' . var_export($matches, true));
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}
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},
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$operation
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);
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}
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return $operation;
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}
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function evaluateParentheses($operation)
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{
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$result = preg_replace_callback('/\(([^\)\(]+)\)/', static function ($matches) {
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return evaluateOperation($matches[1]);
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}, $operation);
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if ($result === $operation || $result === null) {
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return $operation;
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}
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return evaluateParentheses($result);
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}
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