public static SudokuPiece RestoreLatestBackup()
{
Sudoku.ClearData();
BackupData backup = BackupDataStack.Peek();
for (int i = 0; i < 81; i++)
{
if (backup.PiecesFilled.Keys.Contains(i))
{
Sudoku.Pieces[i].InsertValue(backup.PiecesFilled[i]);
}
else
{
Sudoku.Pieces[i].RestoreToUnfilled(backup.PiecesUnfilled[i]);
}
}
return(backup.ChangedPiece);
}
public static void SetBackup(SudokuPiece changedPiece)
{
BackupData backup = new BackupData(Sudoku.PiecesFilled, changedPiece);
for (int i = 0; i < 81; i++)
{
if (Sudoku.Pieces[i].IsFilled)
{
backup.PiecesFilled.Add(i, Sudoku.Pieces[i].Value);
}
else
{
List <string> possibleNumbers = new List <string>();
possibleNumbers.AddRange(Sudoku.Pieces[i].PossibleNumbers);
backup.PiecesUnfilled.Add(i, possibleNumbers);
}
}
BackupDataStack.Push(backup);
}