SudokuLib

A Sudoku library, which targets .NET Standard, supports generating and solving game boards

Project SudokuLib is a library containing 2 namespaces whose classes can be used directly depending on your purpose

1. Sudoku.Generator namespace

This is the low level library. It has a generator which can be used to generate new game boards and a solver which can be used to solve game boards with pre-filled values. Both are derived from a generator base GeneratorBase. This class is where the backtracking algorithm implemented. You can use this part of the library to develop your own game or a game solver.

Usages

• Generator usages

  • Generate a game board

  int x = 3, y = 2;
  var game = new SudokuGenerator(x, y, Processor);
  game.Generate();
  
  bool Processor(int[][] contents)
  {
      // Here we have a game board stored in argument contents, we can store or process it (whatever we want)
  
      // return false if we want to stop generating a new game board, otherwise the generator continues to generate a different game board
      return false;
  }

  • Create a permutation

  int x = 2, y = 2;
  var game = new SudokuGenerator(x, y, null);
  int[] values = game.GetPermutation();

  For example, we have the following goard board

  1	2	3	4
  3	4	1	2
  2	1	4	3
  4	3	2	1

  When using SudokuGenerator.GetPermuation we will get a random permuation of the set [1, 2, 3, 4], let say [2 4 1 3]
  That means we will transform our game board with this map

  1 ⟶ 2  
  2 ⟶ 4  
  3 ⟶ 1  
  4 ⟶ 3  
  

  Now we have another gameboard

  2	4	1	3
  1	3	2	4
  4	2	3	1
  3	1	4	2

  In fact, SudokuGenerator.Generate always generates game boards with the first row is a sequence from 1 -> max number. So we have to use a permuation to create a random game board.

  • Create a random mark

  int x = 2, y = 2, numberOfOpenBoxes = 5;
  var game = new SudokuGenerator(x, y, null);
  var mask = game.CreateRandomMask(numberOfOpenBoxes);
  // If mask[i][j] is true then the value at coordinate (i, j) is revealed to user

  If we have a game board like this

  2	4	1	3
  1	3	2	4
  4	2	3	1
  3	1	4	2

  and we get the following mask after calling CreateRandomMask

  true	true	true	false
  false	false	false	false
  false	false	true	true
  false	false	false	false

  true means the corresponding value is displayed to user, false means user has to fill it

  then we will display the game board to user like this

  2	4	1	?
  ?	?	?	?
  ?	?	3	1
  ?	?	?	?

• Solver usage

  Provide a gameboard with missing values denoted with 0, SodokuSolver will find complete game boards for us

  int X = 3, Y = 3;
  int[][] presetBoard =
  {
      new int[]{4, 0, 0,   2, 0, 6,   1, 7, 0},
      new int[]{0, 9, 0,   5, 0, 3,   0, 0, 0},
      new int[]{0, 5, 0,   0, 7, 0,   6, 9, 0},
  
      new int[]{0, 0, 0,   7, 3, 0,   0, 1, 0},
      new int[]{0, 0, 0,   0, 5, 0,   2, 0, 9},
      new int[]{0, 0, 0,   0, 4, 1,   0, 0, 6},
  
      new int[]{0, 4, 5,   0, 6, 0,   0, 0, 8},
      new int[]{0, 7, 8,   4, 0, 0,   5, 0, 0},
      new int[]{0, 0, 6,   3, 0, 5,   0, 0, 0}
  };
  var solver = new SudokuSolver(X, Y, Processor);
  solver.InitializeBoard(presetBoard);
  solver.Solve();
  
  bool Processor(int[][] contents)
  {
      // We have the complete goard board stored in agument contents here
  
      // return true if we want to find all solutions, otherwise it will stop finding after getting the first one
      return true;
  }

2. SudokuLib.Game namespace

This is a higher level of the library and it uses Sudoku.Generator behind. It is like back-end of the game, almost forms a game without a view. If you use these classes there, you just need to implement your own game view.

Currently it has 4 classes

• Enum GameLevel represents game levels
• GameBox a box which is coressponding to a number in the game board
• GameBoard provide basic operations to the game board
• SudokuGame inherits functionality from GameBoard and uses a SudokuGenerator to generate game board

SudokuUWP

There is also a complete Sudoku game based on this library SudokuUWP written using UWP. It is using SudokuGame class for backing process. Here is a screenshot of it

To-do list

• Develope a game solver UI