/// <summary>
/// Time complexity: O(log(n)).
/// </summary>
public T Extract()
{
if (heapForest.Head == null)
{
throw new Exception("Empty heap");
}
var minMaxTree = heapForest.Head;
var current = heapForest.Head;
//find minMaximum tree
while (current.Next != null)
{
current = current.Next;
if (comparer.Compare(minMaxTree.Data.Value, current.Data.Value) > 0)
{
minMaxTree = current;
}
}
//remove tree root
heapForest.Delete(minMaxTree);
var newHeapForest = new DoublyLinkedList <BinomialHeapNode <T> >();
//add removed roots children as new trees to forest
foreach (var child in minMaxTree.Data.Children)
{
child.Parent = null;
newHeapForest.InsertLast(child);
}
mergeSortedForests(newHeapForest);
meld();
removeMapping(minMaxTree.Data.Value, minMaxTree.Data);
Count--;
return(minMaxTree.Data.Value);
}
/// <summary>
/// O(log(n)) complexity
/// </summary>
/// <returns></returns>
public T ExtractMax()
{
if (heapForest.Head == null)
{
throw new Exception("Empty heap");
}
var maxTree = heapForest.Head;
var current = heapForest.Head;
//find maximum tree
while (current.Next != null)
{
current = current.Next;
if (maxTree.Data.Value.CompareTo(current.Data.Value) < 0)
{
maxTree = current;
}
}
//remove tree root
heapForest.Delete(maxTree);
var newHeapForest = new DoublyLinkedList <BinomialHeapNode <T> >();
//add removed roots children as new trees to forest
foreach (var node in maxTree.Data.Children)
{
node.Parent = null;
newHeapForest.InsertLast(node);
}
MergeSortedForests(newHeapForest);
Meld();
Count--;
return(maxTree.Data.Value);
}