Perl Weekly Challenge 388: Generating Dyck Words With Recursive Algorithms

The Perl Weekly Challenge 388 tasks participants with generating all valid Dyck words of order n — strings of length 2n using 'U' and 'D' characters where no prefix contains more D's than U's. Named after mathematician Walther von Dyck, the concept is analogous to balanced parentheses and grid paths constrained within a 45-degree wedge. The author solved the problem using a recursive algorithm inspired by the CPAN module Math::DyckWords, building each string one character at a time while enforcing the prefix constraint. Default parameter values in the recursive function track the current word, character counts, and recursion depth. The implementation also exploits a natural reverse-alphabetical ordering produced by the recursion, avoiding an explicit sort step.