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<?php function isCorrect($string) { $len = strlen($string); $stack = array(); for( $i = 0; $i < $len; ++$i) { if ( $string[$i] == '(' ) array_push($stack, $string[$i]); elseif( $string[$i] == ')' ) { if ( empty($stack) === false ) array_pop($stack); else return false; } } return empty($stack); } $string = '((()))'; var_dump(isCorrect($string)); //var_dump(isCorrect($string)); //var_dump(strlen($string) % 2); //assert(isCorrect('') === true); //assert(isCorrect('()') === true); //assert(isCorrect('{()}') === true); //assert(isCorrect('{()}{}') === true); //assert(isCorrect('(())') === true); //assert(isCorrect('{({({({()})})})}') === true); //assert(isCorrect('{(})') === false);

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