Use your local runtime, then review the reference solution
A PRACTICAL PLAN
Work through Valid parentheses with intent.
Translate the contract.Turn the requirements into a short checklist before editing your-solution.py.
Use the example as evidence.Predict the result for the supplied input, then add one boundary case such as an empty value, a limit, or unexpected input.
Review the implementation.Compare your choices against solution.py only after a real attempt.
EXERCISE FAQ
Before you move on.
What does “Valid parentheses” teach?
This intermediate Python exercise focuses on Python. Its requirements define the exact behavior to implement before you write code.
How should I validate this Python solution?
Start with the displayed example input and expected output, then test a boundary case suggested by the requirements. Write and compile the starter in your local Python environment, exercise the example and edge cases, then compare your approach with solution.py.
When should I open the reference solution?
Attempt Valid parentheses first. Then open the read-only solution file to compare the contract, edge-case handling, and implementation choices—not simply to copy the final code.
