/// <summary>
/// Put the new node into the left side of the old node.
/// </summary>
/// <param name="oldNode">The old node.</param>
/// <param name="newNode">The new node.</param>
public void PutLeft(DlxNode *oldNode, DlxNode *newNode)
{
newNode->Left = oldNode->Left;
newNode->Right = oldNode;
oldNode->Left->Right = newNode;
oldNode->Left = newNode;
}
/// <summary>
/// Put the new node into the up side of the old node.
/// </summary>
/// <param name="oldNode">The old node.</param>
/// <param name="newNode">The new node.</param>
public void PutUp(DlxNode *oldNode, DlxNode *newNode)
{
// If the old node is the head node, we should insert the new node into the tail.
// However, to be honest, the relative position between the old node and the new node
// is unnecessary, because we determine the position without using those two nodes.
newNode->Up = oldNode->Up;
newNode->Down = oldNode;
oldNode->Up->Down = newNode;
oldNode->Up = newNode;
oldNode->Size++;
newNode->Column = oldNode;
}
/// <summary>
/// Uncover the specified column.
/// </summary>
/// <param name="c">The column.</param>
public void Uncover(DlxNode *c)
{
for (var row = c->Up; row != c; row = row->Up)
{
for (var j = row->Left; j != row; j = j->Left)
{
j->Column->Size++;
j->Down->Up = j;
j->Up->Down = j;
}
}
c->Right->Left = c;
c->Left->Right = c;
}
/// <summary>
/// Cover the specified column.
/// </summary>
/// <param name="c">The column.</param>
public void Cover(DlxNode *c)
{
// Remove the node from the head.
c->Right->Left = c->Left;
c->Left->Right = c->Right;
for (var row = c->Down; row != c; row = row->Down)
{
for (var j = row->Right; j != row; j = j->Right)
{
j->Down->Up = j->Up;
j->Up->Down = j->Down;
j->Column->Size--;
}
}
}
