public Node(RowHeader r, ColumnHeader c)
{
row = r;
column = c;
}
public bool DLSolve()
{
if (columns.Count == 0)
{
return(true);
}
//MessageBox.Show("Rows: " + rows.Count.ToString() + "\nConstraints: " + columns.Count);
int minCount = columns.Min(x => x.memberCount);
if (minCount == 0)
{
return(false);
}
ColumnHeader currentColumn = columns.Where(x => x.memberCount == minCount).ToArray()[0];
List <RowHeader> rowsToChoose = new List <RowHeader>();
Node curNode = currentColumn.firstNode;
do
{
rowsToChoose.Add(curNode.row);
curNode = curNode.down;
} while (curNode != currentColumn.firstNode);
while (rowsToChoose.Count > 0)
{
int colBefore = columns.Count;
int rowBefore = rows.Count;
RowHeader currentRow = chooseRow(rowsToChoose);
if (rowsToChoose.Contains(currentRow))
{
rowsToChoose.Remove(currentRow);
Node columnNode = currentRow.firstNode; //Indexes the column we're working on
partialSolution.Add(currentRow);
do
{
constraintRemove(columnNode.column);
columnNode = columnNode.right;
} while (columnNode != currentRow.firstNode);
if (DLSolve())
{
return(true);
}
else
{
//Reverse the above process.
columnNode = currentRow.firstNode; //Indexes the column we're working on
partialSolution.Remove(currentRow);
do
{
constraintAdd(columnNode.column);
columnNode = columnNode.right;
} while (columnNode != currentRow.firstNode);
if (columns.Count != colBefore)
{
throw new Exception();
}
if (rows.Count != rowBefore)
{
throw new Exception();
}
}
}
}
return(false);
}
