An ad-free Sudoku app on Android which allows customized board

Question

I'm looking for Sudoku app on Android with the following required features:

• Free of charge
• Ad-free
• Let user input their own board and play
• Let user mark cell with possible candidates

It would also be good if the app has the following features, but these are optional:

• Automatically mark cell with possible candidates
• Automated solver

This online solver would be a good example of what I'm looking for.

Answer 1

THE free (as in free speech and not just in free beer) sudoku app that comes in my mind is OpenSudoku:

• It is free in both ways
• For sure also ad-free
• Several input methods
• You can input possible candidates
• Auto-fill all possible candidates
• You can create your own boards
• You can import/export complete folders of boards (some additional and further nearly 15000(!) boards)
• Save current state (if you have to trial and error)