Sudoku Lab
The Game
In the words of Wikipedia, Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9 × 9 grid with digits so that each column, each row, and each of the nine 3 × 3 boxes contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution.
Our game screen shows the grid with optional row and column labels, the keypad to enter the numbers or notes and the Num / Notes / Trace mode switch.
In the Num mode, the tap on the keypad enters that number in the highlighted cell (A5 in the picture).
In the Notes mode, that toggles the corresponding candidate in the highlighted cell.
In the Trace mode, the tap doesn't change the content of the screen, but simply toggles boldness of the tapped number in the notes, to help you trace some patterns.
Swipe down gesture toggles the action toolbar that allows you to restart the same game, start a new game, auto-fill the notes or request a hint.
The "New Game" button brings up a selection page where you can choose the next game in any of the difficulty levels.
Please note that the games that were already solved show the time taken in green ant he buttom onf that game's cell.
Settings
Swipe up gesture brings up the Settings menu:
Mode - select "Play" or "Practice” mode.
Show timer - show or hide the game timer.
Show grid labels - show or hide the rows and columns labels.
Flag errors immediately - if selected, shows an error when the number is not placed correctly.
Hint
When Hint is requested, the hint pops up at the top of the screen, above the grid.
It contains the name of the strategy that can be used for the next move, the location of the cell that strategy was based on, and the suggested action.
There are three action buttons:
Do it - performs the suggested action.
Explain - shows additional details about the suggested move.
Close - simply closes the Hint screen and lets you proceed with the game.
Please note that the strategy's source cells are highlighted in green, and the target cells - in yellow.
Explain
When Explain button is tapped in the Hint page, the detailed explanation pops up at the bottom of the screen, below the grid.
It contains the name of the strategy that can be used for the next move, the location of the cell that strategy was based on, and the suggested action.
There are two action buttons:
Do it - performs the suggested action.
Close - closes the Explain page, while the Hint page is still open.
Practice
When New Game button is tapped in the Practice mode, the Pick strategies screen is presented.
It contains the list of the implemented strategies with Yes, Maybe and No switches.
The tap on the Generate button will start populating the table with the puzzles according to your selection:
Yes - the strategy is required to solve the puzzle.
Maybe - the strategy may be required to solve the puzzle.
No - the strategy is not required to solve the puzzle.
This helps you practice solving the Sudoku puzzles concentrating on specific strategies.
Please note the Forward button in the Practice mode.
When tapped, it applies trivial strategies (resolving naked or hidden singles), so that you can concentrating on the chosen strategies.