[硕.Love Python] FibonacciHeap(F堆 & 斐波那契堆)

class Node(object):
    __slots__ = [
        'data', 'child', 'left', 'right',
        'degree', 'parent', 'childCut',
    ]

    def __init__(self, data):
        self.data = data
        self.child = None
        self.left = None
        self.right = None
        self.degree = 0

        self.parent = None
        self.childCut = False

    def __str__(self):
        return str(self.data)

    __repr__ = __str__

class FibonacciHeap(object):
    MAX_DEGREE = 20

    def __init__(self):
        self.root = None

    def combine(self, heap):
        self._dlistCombine(self.root, heap.root)

        if heap.root.data < self.root.data:
            self.root = heap.root

    def insert(self, node):
        if self.root is None:
            self.root = node
            self._initSiblingList(node)
        else:
            self._addSibling(self.root, node)
            if node.data < self.root.data:
                self.root = node

    def pop(self):
        if self.root is None:
            raise ValueError('pop from empty heap.')

        res = self.root
        self._clearParent(self.root.child)

        children = self.root.child
        siblings = self._dlistDelete(self.root)

        self.root = self._rebuild(children, siblings)

        return res

    def delete(self, node):
        if node is self.root:
            self.pop()
        else:
            parent = node.parent
            self._deleteChild(parent, node)
            if node.child:
                self._clearParent(node.child)
                self._dlistCombine(self.root, node.child)

            if parent:
                self._cascadingCut(parent)

    def decrease(self, node, k):
        print node.data, k
        node.data -= k
        print node.data
        parent = node.parent
        if parent and node.data < parent.data:
            self._deleteChild(parent, node)
            self._clearParent(node, False)
            self._addSibling(self.root, node)
            self._cascadingCut(parent)

        if node.data < self.root.data:
            self.root = node

    def _cascadingCut(self, node):
        while node.parent and node.childCut:
            parent = node.parent
            self._deleteChild(parent, node)
            self._addSibling(self.root, node)
            node = parent

        if node.parent:
            node.childCut = True

    def _rebuild(self, children, siblings):
        if children is None and siblings is None:
            return None

        treeArr = [None] * FibonacciHeap.MAX_DEGREE
        self._combineTrees(treeArr, children)
        self._combineTrees(treeArr, siblings)

        head = None
        treeIterator = iter(treeArr)

        for node in treeIterator:
            if node:
                break

        root = head = prev = node
        for node in treeIterator:
            if node:
                prev.right = node
                node.left = prev
                prev = node
                if node.data < root.data:
                    root = node

        head.left = prev
        prev.right = head

        return root

    def _combineTrees(self, treeArr, head):
        if head is None:
            return 

        node = head
        while True:
            tmp = node
            node = node.right

            for i in xrange(tmp.degree, len(treeArr)):
                if treeArr[i] is None:
                    break
                tmp = self._joinTree(tmp, treeArr[i])
                treeArr[i] = None
            else:
                raise Exception('max degree')
            treeArr[i] = tmp
            if node is head:
                break

    def _joinTree(self, tree1, tree2):
        if tree2.data < tree1.data:
            tree1, tree2 = tree2, tree1

        self._addChild(tree1, tree2)
        return tree1

    def _dlistInit(self, head):
        head.left = head.right = head

    def _dlistCombine(self, head1, head2):
        r1 = head1.right
        l2 = head2.left

        head1.right = head2
        head2.left = head1
        r1.left = l2
        l2.right = r1

    def _dlistInsert(self, head, node):
        node.left = head
        node.right = head.right 

        node.right.left = node
        head.right = node

    def _dlistDelete(self, node):
        if node.left is node:
            newHead = None
        else:
            node.left.right = node.right
            node.right.left = node.left
            newHead = node.right

        return newHead

    _initSiblingList = _dlistInit
    _addSibling = _dlistInsert

    def _addChild(self, parent, child):
        if parent.child is None:
            parent.child = child
            self._initSiblingList(child)
        else:
            self._addSibling(parent.child, child)
        child.parent = parent
        child.childCut = False
        parent.degree += 1

    def _deleteChild(self, parent, child):
        head = self._dlistDelete(child)
        if parent:
            parent.child = head
            parent.degree -= 1
            child.parent = None

    def _clearParent(self, head, islist=True):
        if head:
            head.parent = None
            if islist:
                node = head.right
                while node is not head:
                    node.parent = None
                    node = node.right