[Language/Tool]: [Algorithm or Concept]

# Naive implementation — establishes correctness
def solution_v1(data):
    """
    Brief description.

    Args:
        data: input description
    Returns:
        output description
    """
    pass

# Verify correctness
assert solution_v1([1, 2, 3]) == expected
assert solution_v1([]) == edge_case

# Optimized implementation — explain what changed and why
def solution_v2(data):
    pass

# Production version — error handling, typing, docstrings
from typing import List

def solution_final(data: List[int]) -> int:
    """Production implementation with full type hints."""
    if not data:
        raise ValueError("Input cannot be empty")
    pass

[sample input data]

[expected output]