private static BoardSquare[,] BuildBoard(string str)
{
Debug.Assert(str.Length == 81);
const int chunkSize = 9;
var boardRows = Enumerable
.Range(0, str.Length / chunkSize)
.Select(i => str.Substring(i * chunkSize, chunkSize))
.ToList();
var board = new BoardSquare[9, 9];
for (var r = 0; r < boardRows.Count; r++)
{
var row = boardRows[r];
Debug.Assert(row.Length == 9);
for (var c = 0; c < row.Length; c++)
{
board[r, c] = new BoardSquare(r, c, (int)char.GetNumericValue(row[c]));
}
}
return(board);
}
private void SetMatrixValues(IList <bool> mRow, BoardSquare boardSquare)
{
var row = boardSquare.GetRowIndex();
var column = boardSquare.GetColumnIndex();
var value = boardSquare.GetValue() - 1;
int RegionIndex()
{
var regionSize = (int)Math.Sqrt(size);
var regionNum1 =
(int)Math.Floor(row / (double)regionSize) * regionSize +
(int)Math.Floor(column / (double)regionSize);
return(regionNum1);
}
// In order, sets of 81 indexes
var positionConstraint = row * size + column;
var rowConstraint = size * size + row * size + value;
var columnConstraint = size * size * 2 + column * size + value;
var regionConstraint = size * size * 3 + RegionIndex() * size + value;
// Initialize matrix where the constraint is satisfied
mRow[positionConstraint] = true;
mRow[rowConstraint] = true;
mRow[columnConstraint] = true;
mRow[regionConstraint] = true;
}
private IEnumerable <BoardSquare> GetNeighbours(BoardSquare currentSquare)
{
var Row = currentSquare.GetRowIndex();
var Column = currentSquare.GetColumnIndex();
var SubBoard = currentSquare.GetSubBoard(Column, Row);
var PlacedValues = new List <BoardSquare>();
PlacedValues.AddRange(_board.GetRow(Row));
PlacedValues.AddRange(_board.GetColumn(Column));
PlacedValues.AddRange(_board.GetSubBoard(SubBoard));
return(PlacedValues);
}
private (DoublyLinkedList <bool> linkedList, List <BoardSquare> squares) CalculateMatrix()
{
var matrix = new List <bool[]>();
var squares = new List <BoardSquare>();
for (var row = 0; row < size; row++)
{
for (var column = 0; column < size; column++)
{
var boardSquare = _board.GetBoardSquare(row, column);
if (boardSquare.IsEmpty())
{
for (var value = 1; value <= size; value++)
{
var square = new BoardSquare(row, column, value);
matrix.Add(new bool[listLength]);
SetMatrixValues(matrix.Last(), square);
squares.Add(square);
}
continue;
}
matrix.Add(new bool[listLength]);
SetMatrixValues(matrix.Last(), boardSquare);
squares.Add(boardSquare);
}
}
var linkedList = new DoublyLinkedList <bool>(listLength);
linkedList.ProcessMatrix(matrix);
return(linkedList, squares);
}