refactor: reorganize parking system solution to new structure

[kobukuro]

Move LeetCode 1603 (Design Parking System) from flat Design/ directory to standardized problems/easy/design_parking_system_1603/ structure.

Improvements:

• Convert to PEP 8 compliant snake_case naming (add_car, spaces)
• Add pytest test suite with documentation
• Simplify conditional logic in add_car method
• Follow project's standardized directory layout

[Copilot]

Pull request overview

This PR refactors LeetCode problem 1603 (Design Parking System) from the legacy flat Design/ directory structure to the standardized problems/easy/design_parking_system_1603/ layout. The implementation converts method names from camelCase to PEP 8 compliant snake_case and adds a pytest test suite with documentation.

Changes:

• Reorganizes files into standardized problem directory structure with solution.py, test_solution.py, and __init__.py
• Converts method name from addCar to add_car following PEP 8 snake_case convention
• Adds pytest test suite with LeetCode example test case and documentation

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 4 comments.

File	Description
problems/easy/design_parking_system_1603/solution.py	ParkingSystem class implementation with snake_case naming and dictionary-based space tracking
problems/easy/design_parking_system_1603/test_solution.py	Pytest test class with helper method for testing multiple constructor/method calls
problems/easy/design_parking_system_1603/init.py	Empty module initialization file following project structure

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[Copilot]

The TestSolution class doesn't inherit from BaseTestSolution, which is the common pattern for most test files in the codebase. While not strictly required for this simple test, inheriting from BaseTestSolution provides consistency with other tests and access to utilities like timeout handling. Consider changing to "class TestSolution(BaseTestSolution):" and adding the import "from tests.base_test import BaseTestSolution".

Suggested change

	class TestSolution:
	from tests.base_test import BaseTestSolution
	class TestSolution(BaseTestSolution):

[Copilot]

The add_car method doesn't validate that car_type is valid (1, 2, or 3). If an invalid car_type is passed, this will raise a KeyError when accessing self.spaces[car_type]. While LeetCode constraints may guarantee valid inputs, defensive programming suggests adding validation or at least a comment about the expected input range. Consider adding a check or documenting the assumption that car_type will always be in range [1, 3].

[Copilot]

The dictionary formatting is inconsistent with PEP 8 style for multiline dictionaries. When a dictionary is split across multiple lines, each key-value pair should be on its own line with consistent indentation, or the opening brace should be followed by a newline. Consider formatting as either: self.spaces = {1: big, 2: medium, 3: small} (single line) or with proper alignment:

self.spaces = {
    1: big,
    2: medium,
    3: small
}

Suggested change

	self.spaces = {1: big,
	2: medium,
	3: small}
	self.spaces = {
	1: big,
	2: medium,
	3: small
	}