// <summary>Implements collections.UpdatableCollection.take. Time
// complexity: O(log n). Takes the least element. @see
// collections.UpdatableCollection#take.</summary>
// <returns>A T object.</returns>
public T Pop()
{
if (this.countValue != 0)
{
RBCell p = this.treeValue.leftmost();
T v = p.element();
this.treeValue = p.delete(this.treeValue);
this.decCount();
return(v);
}
return(default(T));
}
private bool remove_(T element, bool allOccurrences)
{
var ret = false;
while (this.countValue > 0)
{
RBCell p = this.treeValue.find(element, this.cmpValue);
if (p != null)
{
this.treeValue = p.delete(this.treeValue);
this.decCount();
ret = true;
if (!allOccurrences)
{
return(ret);
}
}
else
{
break;
}
}
return(ret);
}
// <summary>Delete the current node, and then rebalance the tree it is
// in.</summary>
// <param name='root'>The root of the current tree.</param>
// <returns>The new root of the current tree. Rebalancing can change
// the root.</returns>
public RBCell delete(RBCell root)
{
// if strictly internal, swap contents with successor and then delete it
if (this.leftValue != null && this.rightValue != null)
{
RBCell s = this.successor();
this.copyContents(s);
return(s.delete(root));
}
// Start fixup at replacement node, if it exists
RBCell replacement = this.leftValue ?? this.rightValue;
if (replacement != null)
{
// link replacement to parent
replacement.parentValue = this.parentValue;
if (this.parentValue == null)
{
root = replacement;
}
else if (this == this.parentValue.leftValue)
{
this.parentValue.leftValue = replacement;
}
else
{
this.parentValue.rightValue = replacement;
}
// null out links so they are OK to use by fixAfterDeletion
this.leftValue = null;
this.rightValue = null;
this.parentValue = null;
// fix replacement
if (this.colorValue)
{
root = replacement.fixAfterDeletion(root);
}
return(root);
}
if (this.parentValue == null) // exit if we are the only node
// if no children, use self as phantom replacement
// and then unlink
{
return(null);
}
if (this.colorValue)
{
root = this.fixAfterDeletion(root);
}
// Unlink (Couldn't before since fixAfterDeletion needs parent ptr)
if (this.parentValue != null)
{
if (this == this.parentValue.leftValue)
{
this.parentValue.leftValue = null;
}
else if (this == this.parentValue.rightValue)
{
this.parentValue.rightValue = null;
}
this.parentValue = null;
}
return(root);
}