Class mxFibonacciHeap

  • public class mxFibonacciHeap
    extends java.lang.Object
    This class implements a priority queue.
    • Constructor Detail

      • mxFibonacciHeap

        public mxFibonacciHeap()
    • Method Detail

      • getNode

        public mxFibonacciHeap.Node getNode​(java.lang.Object element,
                                            boolean create)
        Returns the node that represents element.
        element - the element whose node to find
        create - whether to create
        the node representing the specified element
      • isEmpty

        public boolean isEmpty()
        Returns true if the queue is empty.
        whether the queue is empty
      • decreaseKey

        public void decreaseKey​(mxFibonacciHeap.Node x,
                                double k)
        Decreases the key value for a heap node, given the new value to take on. The structure of the heap may be changed and will not be consolidated.

        Running time: O(1) amortized

        x - Node whose value should be decreased.
        k - New key value for node x.
        java.lang.IllegalArgumentException - Thrown if k is larger than x.key value.
      • delete

        public void delete​(mxFibonacciHeap.Node x)
        Deletes a node from the heap given the reference to the node. The trees in the heap will be consolidated, if necessary. This operation may fail to remove the correct element if there are nodes with key value -Infinity.

        Running time: O(log n) amortized

        x - The node to remove from the heap.
      • insert

        public void insert​(mxFibonacciHeap.Node node,
                           double key)
        Inserts a new data element into the heap. No heap consolidation is performed at this time, the new node is simply inserted into the root list of this heap.

        Running time: O(1) actual

        node - new node to insert into heap
        key - key value associated with data object
      • min

        public mxFibonacciHeap.Node min()
        Returns the smallest element in the heap. This smallest element is the one with the minimum key value.

        Running time: O(1) actual

        Returns the heap node with the smallest key.
      • removeMin

        public mxFibonacciHeap.Node removeMin()
        Removes the smallest element from the heap. This will cause the trees in the heap to be consolidated, if necessary. Does not remove the data node so that the current key remains stored.

        Running time: O(log n) amortized

        Returns the node with the smallest key.
      • size

        public int size()
        Returns the size of the heap which is measured in the number of elements contained in the heap.

        Running time: O(1) actual

        Returns the number of elements in the heap.
      • union

        public static mxFibonacciHeap union​(mxFibonacciHeap h1,
                                            mxFibonacciHeap h2)
        Joins two Fibonacci heaps into a new one. No heap consolidation is performed at this time. The two root lists are simply joined together.

        Running time: O(1) actual

        h1 - The first heap.
        h2 - The second heap.
        Returns a new heap containing h1 and h2.
      • cascadingCut

        protected void cascadingCut​(mxFibonacciHeap.Node y)
        Performs a cascading cut operation. This cuts y from its parent and then does the same for its parent, and so on up the tree.

        Running time: O(log n); O(1) excluding the recursion

        y - The node to perform cascading cut on.
      • consolidate

        protected void consolidate()
        Consolidates the trees in the heap by joining trees of equal degree until there are no more trees of equal degree in the root list.

        Running time: O(log n) amortized

      • cut

        protected void cut​(mxFibonacciHeap.Node x,
                           mxFibonacciHeap.Node y)
        The reverse of the link operation: removes x from the child list of y. This method assumes that min is non-null.

        Running time: O(1)

        x - The child of y to be removed from y's child list.
        y - The parent of x about to lose a child.
      • link

        protected void link​(mxFibonacciHeap.Node y,
                            mxFibonacciHeap.Node x)
        Make node y a child of node x.

        Running time: O(1) actual

        y - The node to become child.
        x - The node to become parent.