/// <summary>
/// Fills an existing <see cref="SudokuPuzzle"/> with numbers.
/// </summary>
/// <param name="sudoku">The puzzle to fill with numbers.</param>
/// <exception cref="ArgumentNullException"><c><paramref name="sudoku"/></c> is <c>null</c>.</exception>
public static void AddNumbers(SudokuPuzzle sudoku)
{
if (sudoku is null)
{
throw new ArgumentNullException(nameof(sudoku));
}
sudoku.DisablePossible = true;
SudokuSolver.RecursiveSolve(sudoku);
sudoku.DisablePossible = false;
sudoku.ResetPossible();
sudoku.ClearReadOnlyProperties();
sudoku.SetSolutions();
}
/// <summary>
/// Parses the text representing a single <see cref="SudokuPuzzle"/>.
/// </summary>
/// <param name="s">The text to parse.</param>
/// <returns>A <see cref="SudokuPuzzle"/> representation of <c><paramref name="s"/></c>.</returns>
/// <exception cref="ArgumentNullException"><c><paramref name="s"/></c> is <c>null</c>.</exception>
/// <exception cref="FormatException"><c><paramref name="s"/></c> is not in the correct format.</exception>
public static SudokuPuzzle Deserialize(String s)
{
if (s is null)
{
throw new ArgumentNullException(nameof(s));
}
String[] split = s.Split(',');
if (split.Length != 5)
{
throw new FormatException();
}
try
{
int size = Int32.Parse(split[0]);
int squared = size * size;
if (!SudokuPuzzle.VerifySize(size))
{
throw new FormatException();
}
SudokuDifficulty difficulty = (SudokuDifficulty)Enum.Parse(typeof(SudokuDifficulty), split[1], true);
int[] numbers = new int[squared], solutions = new int[squared];
bool[] readOnly = new bool[squared];
if (split[2].Length != squared || split[3].Length != squared || split[4].Length != squared)
{
throw new FormatException();
}
for (int i = 0; i < squared; i++)
{
numbers[i] = split[2][i] - '0';
solutions[i] = split[3][i] - '0';
readOnly[i] = split[3][i] == '1';
}
SudokuPuzzle puzzle = SudokuPuzzle.Parse(size, difficulty, numbers, solutions, readOnly);
puzzle.ResetPossible();
return(puzzle);
}
catch
{
throw new FormatException();
}
}
/// <summary>
/// Solve the specified <see cref="T:Sudoku.Sudoku"/> puzzle using recursion, otherwise known as "brute-force".
/// </summary>
/// <param name="sudoku">The <see cref="T:Sudoku.Sudoku"/> puzzle to solve.</param>
/// <exception cref="ArgumentNullException"><c><paramref name="sudoku"/></c> is <c>null</c>.</exception>
public static void RecursiveSolve(SudokuPuzzle sudoku)
{
if (sudoku is null)
{
throw new ArgumentNullException(nameof(sudoku));
}
int count = 0;
sudoku.DisablePossible = true;
SudokuSolver.RecursiveSolve(sudoku, 0, 0, ref count);
sudoku.DisablePossible = false;
sudoku.ResetPossible();
}