You are an expert Python programmer.
Write a Python code that defines a function named `solve` which takes two arguments:
- a list of numbers,
- an integer k.
The code must:
- return the k largest numbers in the list in descending order,
- return an empty list if the input list is empty or k <= 0,
- if k is larger than the list length, return the whole list sorted descending,
- not import external libraries unless strictly required.
Important formatting rules:
- Output only valid Python function code, nothing else.
- Enclose the code between <python_code> and </python_code> tags.
- Do not add explanations, comments, or test case.
