private void Exchange(FibonacciHeapNode <K, V> x, FibonacciHeapNode <K, V> y)
{
FibonacciHeapNode <K, V> temp = y;
y = x;
x = temp;
}
/// <summary>
/// union
/// It runs at O(1)
/// </summary>
/// <param name="h1"></param>
/// <param name="h2"></param>
/// <returns></returns>
public static MinFibonacciHeap <K, V> Union(MinFibonacciHeap <K, V> h1, MinFibonacciHeap <K, V> h2)
{
if (h1 == null || h1.minRoot == null)
{
return(h2);
}
if (h2 == null || h2.minRoot == null)
{
return(h1);
}
var heap = new MinFibonacciHeap <K, V>();
heap.minRoot = h1.minRoot;
if (h1.minRoot.Key.CompareTo(h2.minRoot.Key) > 0)
{
heap.minRoot = h2.minRoot;
}
//concatenate the root list of H1 and H2
FibonacciHeapNode <K, V> h1Node = h1.minRoot.RightSibling;
FibonacciHeapNode <K, V> h2Node = h2.minRoot.RightSibling;
h1.minRoot.RightSibling = h2Node;
h2Node.LeftSibling = h1.minRoot;
h2.minRoot.RightSibling = h1Node;
h1Node.LeftSibling = h2.minRoot;
heap.Count = h1.Count + h2.Count;
return(heap);
}
/// <summary>
/// union
/// </summary>
/// <param name="heap"></param>
public void Union(MinFibonacciHeap <K, V> heap)
{
MinFibonacciHeap <K, V> h = Union(this, heap);
Count = h.Count;
minRoot = h.minRoot;
}
/// <summary>
/// insert it runs at O(1). add a node to the rooted list
/// </summary>
/// <param name="key"></param>
/// <param name="val"></param>
public void Insert(K key, V val)
{
Count++;
var newNode = new FibonacciHeapNode <K, V>(key, val);
if (maxRoot == null)
{
maxRoot = newNode;
newNode.LeftSibling = newNode.RightSibling = newNode;
}
else
{
//insert node to the root list
FibonacciHeapNode <K, V> temp = maxRoot.RightSibling;
newNode.RightSibling = temp;
maxRoot.RightSibling = newNode;
newNode.LeftSibling = maxRoot;
temp.LeftSibling = newNode;
if (newNode.Key.CompareTo(maxRoot.Key) > 0)
{
//change the root to biggest one
maxRoot = newNode;
}
}
}
/// <summary>
/// it runs at O(1) amortized
/// </summary>
/// <param name="x"></param>
/// <param name="newKey"></param>
public void DecreaseKey(FibonacciHeapNode <K, V> x, K newKey)
{
if (newKey.CompareTo(x.Key) > 0)
{
throw new Exception("new key is greater than current key");
}
if (newKey.CompareTo(x.Key) == 0)
{
return;
}
x.Key = newKey;
FibonacciHeapNode <K, V> y = x.Parent;
if (y != null && x.Key.CompareTo(y.Key) < 0)
{
//move x from y to root list
Cut(x, y);
CascadingCut(y);
}
if (x.Key.CompareTo(minRoot.Key) < 0)
{
minRoot = x;
}
}
/// <summary>
/// union
/// </summary>
/// <param name="heap"></param>
public void Union(MaxFibonacciHeap <K, V> heap)
{
MaxFibonacciHeap <K, V> h = Union(this, heap);
Count = h.Count;
maxRoot = h.maxRoot;
}
/// <summary>
/// extractMax it runs at O(D(n)) amortized time. D(n) is maximum degree which O(lgn)
/// the max one are removed from heap
/// it's where the delayed work of consolidating trees finally occurs
/// </summary>
/// <returns></returns>
public FibonacciHeapNode <K, V> ExtractMax()
{
if (maxRoot == null || Count <= 0)
{
throw new Exception("Heap is empty");
}
//for each child in maxroot add it in the root list
List <FibonacciHeapNode <K, V> > list = maxRoot.GetChildren();
maxRoot.Child = null;
maxRoot.Degree = 0;
foreach (var node in list)
{
node.Parent = null;
//insert node to root list
FibonacciHeapNode <K, V> right = maxRoot.RightSibling;
node.RightSibling = right;
right.LeftSibling = node;
maxRoot.RightSibling = node;
node.LeftSibling = maxRoot;
}
FibonacciHeapNode <K, V> temp = maxRoot;
FibonacciHeapNode <K, V> tempR = maxRoot.RightSibling;
if (temp == tempR)
{
//no element in heap
maxRoot = null;
Count = 0;
return(temp);
}
//remove maxroot
FibonacciHeapNode <K, V> tempL = maxRoot.LeftSibling;
tempL.RightSibling = tempR;
tempR.LeftSibling = tempL;
//maxRoot may not the max one here
maxRoot = tempR;
Consolidate();
Count--;
return(temp);
}
private void CascadingCut(FibonacciHeapNode <K, V> node)
{
FibonacciHeapNode <K, V> parent = node.Parent;
if (parent != null)
{
if (node.Mark == false)
{
//cut the first child
node.Mark = true;
}
else
{
//cut two children from parent
Cut(node, parent);
CascadingCut(parent);
}
}
}
public List <FibonacciHeapNode <K, V> > GetChildren()
{
List <FibonacciHeapNode <K, V> > list = new List <FibonacciHeapNode <K, V> >();
if (Child == null)
{
return(list);
}
FibonacciHeapNode <K, V> temp = Child;
while (true)
{
list.Add(temp);
temp = temp.RightSibling;
if (temp == Child)
{
break;
}
}
return(list);
}
/// <summary>
/// x.key<=y.key make y a child of x
/// </summary>
/// <param name="y"></param>
/// <param name="x"></param>
private void HeapLink(FibonacciHeapNode <K, V> y, FibonacciHeapNode <K, V> x)
{
FibonacciHeapNode <K, V> temp = y;
FibonacciHeapNode <K, V> yL = y.LeftSibling, yR = y.RightSibling;
yL.RightSibling = yR;
yR.LeftSibling = yL;
y.Parent = x;
x.Degree++;
if (x.Child == null)
{
x.Child = y;
y.LeftSibling = y.RightSibling = y;
}
else
{
FibonacciHeapNode <K, V> t = x.Child.RightSibling;
x.Child.RightSibling = y;
y.LeftSibling = x.Child;
y.RightSibling = t;
t.LeftSibling = y;
}
y.Mark = false;
}
/// <summary>
/// move x from y to root list
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
private void Cut(FibonacciHeapNode <K, V> x, FibonacciHeapNode <K, V> y)
{
y.Degree--;
if (x.LeftSibling == x)
{
y.Child = null;
}
else
{
x.LeftSibling.RightSibling = x.RightSibling;
x.RightSibling.LeftSibling = x.LeftSibling;
}
// add x to the root list
FibonacciHeapNode <K, V> t = minRoot.RightSibling;
minRoot.RightSibling = x;
x.LeftSibling = minRoot;
x.RightSibling = t;
t.LeftSibling = x;
x.Parent = null;
x.Mark = false;
}
/// <summary>
/// insert
/// it runs at O(1)
/// </summary>
/// <param name="key"></param>
/// <param name="val"></param>
public void Insert(K key, V val)
{
var node = new FibonacciHeapNode <K, V>(key, val);
if (minRoot == null)
{
minRoot = node;
node.LeftSibling = node.RightSibling = node;
}
else
{
//insert node to root list
FibonacciHeapNode <K, V> temp = minRoot.RightSibling;
node.RightSibling = temp;
minRoot.RightSibling = node;
node.LeftSibling = minRoot;
temp.LeftSibling = node;
if (node.Key.CompareTo(minRoot.Key) < 0)
{
minRoot = node;
}
}
Count++;
}
/// <summary>
/// it runs at O(D(n)) amortized time. D(n) is maximum degree, which O(lgn)
/// </summary>
/// <param name="node">the node to delete</param>
/// <param name="min">the min value so that we can decrease the node to the root</param>
public void Delete(FibonacciHeapNode <K, V> node, K min)
{
DecreaseKey(node, min);
ExtractMin();
}
/// <summary>
/// constructor
/// </summary>
public MaxFibonacciHeap()
{
Count = 0;
maxRoot = null;
}
/// <summary>
/// it runs at O(D(n)) amortized time. D(n) is maximum degree, which O(lgn)
/// </summary>
/// <param name="node">the node to delete</param>
/// <param name="max">the max value so that we can increase the node to the root</param>
public void Delete(FibonacciHeapNode <K, V> node, K max)
{
IncreaseKey(node, max);
ExtractMax();
}
public MinFibonacciHeap()
{
Count = 0;
minRoot = null;
}
/// <summary>
/// consolidate the heap util every node in the root list have different degree value
/// 1)find two roots x and y in the root list with the same degree. without loss of generality, let x.key <= y.key
/// 2)remove y from the root list, and make y a child of x by calling the HeapLink procedure. the procedure increments the attribute x.degree and clear the mark on y
/// </summary>
private void Consolidate()
{
if (minRoot == null)
{
return;
}
//if arr[i] = y, then y is currently a root with y.degree = i
var arr = new FibonacciHeapNode <K, V> [MaxDegree() + 1];
FibonacciHeapNode <K, V> temp = minRoot;
var rootList = new List <FibonacciHeapNode <K, V> >();
while (true)
{
rootList.Add(temp);
temp = temp.RightSibling;
if (temp == minRoot)
{
break;
}
}
foreach (var fnode in rootList)
{
FibonacciHeapNode <K, V> x = fnode;
int d = fnode.Degree;
while (arr[d] != null)
{
//y must appear before x in the rootList & x and y have same degree
FibonacciHeapNode <K, V> y = arr[d];
if (x.Key.CompareTo(y.Key) > 0)
{
Exchange(x, y);
}
HeapLink(y, x);
arr[d] = null;
d++;
}
arr[d] = x;
}
minRoot = null;
for (int i = 0; i < arr.Length; i++)
{
if (arr[i] != null)
{
if (minRoot == null)
{
minRoot = arr[i];
minRoot.LeftSibling = minRoot.RightSibling = minRoot;
}
else
{
FibonacciHeapNode <K, V> minR = minRoot.RightSibling;
minRoot.RightSibling = arr[i];
arr[i].LeftSibling = minRoot;
arr[i].RightSibling = minR;
minR.LeftSibling = arr[i];
if (minRoot.Key.CompareTo(arr[i].Key) > 0)
{
minRoot = arr[i];
}
}
}
}
}
