/// <summary>
/// Solves the puzzle as best it can. This is the method portraying the logical order of solving.
/// </summary>
/// <param name="s"></param>
/// <param name="c"></param>
/// <returns>integer type board</returns>
public static int[,] Solve(SNode[,] s, Controller c)
{
//untested.Remove(tested[0]);
controller = c;
Load(s); // Loads initial state with predetermined obvious "not-possibles"
while (!IsSolved())
{
// Precedence 0: Solve spaces when only 1 value is possible.
if (NakedSingle())
{
failCount = 0;
continue;
}
// Precedence 1: Remove some possibles with this solve technique. Line/Box Reduction.
if (LineBoxReduction())
{
failCount = 0;
continue;
}
// Precedence 2: Remove some possibles with this solve technique. Naked, Single, Pair, Triplet, Quadruplet, etc...
if (SetLoop())
{
failCount = 0;
continue;
}
// Precedence 3: Remove some possibles with this solve technique. XWing[Row->Col] or XWing[Col->Row]
if (XWingLoop())
{
failCount = 0;
continue;
}
// Precedence 4: Guess a number into a SNode. Hope that it causes contradiction or completed the puzzle.
//if (!guessPlaced)
//{
// BackupSudokuBoard();
// GuessValue();
//}
//else
//{
// if (Contradiction())
// {
// attemptedGuesses.Clear();
//
// RetractSudokuBoardState();
//
// guessedNode = board.Sudoku[guessedNode.columnIndex, guessedNode.rowIndex];
//
// guessedNode.Possibles.Remove(guessedValue);
// }
// else // we didn't gain any knowledge....try a different number on same SNode or different SNode entirely.
// {
// string coord = "" + guessedNode.columnIndex + guessedNode.rowIndex;
//
// if (!attemptedGuesses.ContainsKey(coord))
// attemptedGuesses.Add(coord, new OrderedSet<int>());
//
// attemptedGuesses[coord].Add(guessedValue);
//
// RetractSudokuBoardState();
// GuessValue();
// }
//}
if (failCount > 2)
{
return(SNode.ConvertToOutput(board));
}
failCount++;
}
if (controller != null)
{
string output = "Puzzle Solved!";
controller.PrintStatement(output);
}
return(SNode.ConvertToOutput(board));
} // Solve()