Sudoku - memory game app for iPhone and iPad

The objective is to fill a 9x9 grid with digits so that each column, each row, and each of the nine 3x3 grids that compose the Sudoku (also called “boxes” or “regions”) contains all of the digits from 1 to 9.
You must not repeat the number in the same row, column or grid.
The main features of this game are:
-You can choose the difficulty level that you want.
-If you need help, you can click on the “light bulb” button. It will give you a clue of the next step to follow.
-You can check and correct numbers.
-You can restart the whole game at any time.
-If you get bored of a Sudoku, you have the possibility of just taking up another one.
-Ranking of best scores.
-Autosave of the game. Continue playing another time