Smallest Permutation Greater Than or Equal to a Given Lower Bound

Problem Given a lower bound lowerBound (typically an integer or a digit string), find the smallest permutation (from some given set of digits) whose numeric value is >= lowerBound. Note: The interview note only contains the title and a link. Critical details (where the digits come from, exact I/O format, and edge-case requirements) are missing, so the problem cannot be uniquely reconstructed into a fully implementable statement.