private void Uncover(DataObject headerColumn)
{
foreach (var row in EnumerateNodes(headerColumn, o => o.Up))
{
foreach (var column in EnumerateNodes(row, o => o.Left))
{
column.Down.Up = column;
column.Up.Down = column;
column.Header.Size++;
}
}
headerColumn.Right.Left = headerColumn;
headerColumn.Left.Right = headerColumn;
}
private void InsertDoublyLinkedNode(DataObject left, ColumnObject up, DataObject node)
{
node.InsertHorizontalNode(left.Left, left);
node.InsertVerticalNode(up.Up, up);
node.Header = up;
node.Header.Size++;
}
private void CreateConstraints(uint matrixRow, uint[] matrixColumns, uint row, uint column, uint value)
{
DataObject left = null;
foreach (var matrixColumn in matrixColumns)
{
var node = new DataObject
{
Row = row,
Column = column,
Value = ++value
};
if (left == null)
{
left = node;
}
var up = _columnHeaders[matrixColumn];
_constraintMatrix[matrixRow, matrixColumn] = node;
InsertDoublyLinkedNode(left, up, node);
}
}
private IEnumerable<DataObject> EnumerateNodes(DataObject start, Func<DataObject, DataObject> function)
{
var node = start;
while ((node = function(node)) != start)
{
yield return node;
}
}
private void Cover(DataObject headerColumn)
{
headerColumn.Right.Left = headerColumn.Left;
headerColumn.Left.Right = headerColumn.Right;
foreach (var row in EnumerateNodes(headerColumn, o => o.Down))
{
foreach (var column in EnumerateNodes(row, o => o.Right))
{
column.Down.Up = column.Up;
column.Up.Down = column.Down;
column.Header.Size--;
}
}
}