🧩 Sudoku Solver Assistant (Human-like Strategy)

This Python script is a human-style Sudoku solving assistant. It takes a Sudoku puzzle input (row by row) and attempts to reduce possibilities for each cell using logical deductions — mimicking how a person might approach solving a puzzle step by step.

📋 Features

• Input Sudoku manually via console (as 9 lines of 9 characters each)
• Displays the Sudoku board before and after each solving phase
• Performs constraint-based elimination:
  • ✅ Row checking
  • ✅ Column checking
  • ✅ Box (3×3 subgrid) checking
• Iterates through these checks until no more progress is made
• Final output is a cleaned-up grid with only solved digits shown
• Includes nicely formatted display output for better visualization

🔧 How It Works

The script follows a simple rule-based logic:

1. Row Checking: For each empty cell, eliminate numbers already present in the same row.
2. Column Checking: Further reduce candidates based on the column.
3. Box Checking: Finally, reduce based on the 3×3 subgrid.
4. Repeat the above checks in a loop until the board state no longer changes.
5. Hint Remover: All remaining multi-digit candidates are removed for a clean final display.

It doesn’t use any brute-force or backtracking — just pure logical deductions like a human might attempt.

✅ Example

Enter 1st row of Sudoku (no gaps between numbers!):53  7    
Enter 2nd row of Sudoku (no gaps between numbers!):6  195   
Enter 3rd row of Sudoku (no gaps between numbers!): 98    6 
...

Intermediate states will be printed, ending with something like:

Final sudoku:
 +-----------------+-----------------+-----------------+
 |  5   .   3  |  .   7   .  |  .   .   .  | 
 |  6   .   .  |  1   9   5  |  .   .   .  | 
 |  .   9   8  |  .   .   .  |  .   6   .  | 
...

🧪 Testing

The script includes several commented-out test puzzles taken from newspapers, Sudoku magazines, and Wikipedia. Just uncomment any of them to use instead of live input.

🛠️ Requirements

• Python 3.x
• No external libraries needed (uses only copy for deep copying)

🗂️ File Structure

• sudokuHelper.py — main script file
• README.md — this file

🚀 Future Improvements

• Implement logical strategies like:
  • Naked/hidden singles/pairs
  • Pointing pairs/triples
  • X-Wing/Swordfish
• Optional GUI for better interaction
• Web or mobile interface

📜 License

No.