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

2019-11-08 03:27:54

字體：大中小

來源：轉載

供稿：網友

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

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