Improve Performance with Expected Value Checks

[wesleybertipaglia]

Description

Optimize performance by calculating and storing possible valid numbers for each empty cell during play or generation.

Why

Efficient value checking can make puzzle generation and solving faster and smoother, especially for larger boards or hinting logic.

Goals

• Maintain a list of candidate values for each empty cell.
• Recalculate candidates only when necessary (e.g., after input).

Suggested Implementation

• Use sets or arrays to track valid options per cell.
• Consider updating candidates in real-time or batch.