Artemis: Refactor Methods in Single Class for Enhanced Performance

[artemis-gen-ai]

This pull request refactors the sumRange, maxArray, and sumModulus methods in the Single class to improve efficiency and simplify the code. Key changes include:

1. sumRange: Replaced the loop-based summation with a direct mathematical formula for constant time calculation.
2. maxArray: Updated to initialize max with the first element of the array to correctly identify the maximum value, even with negative numbers.
3. sumModulus: Streamlined to maintain a running total instead of using an intermediate collection, enhancing clarity and reducing overhead.

These improvements lead to better performance and maintainability.