forked from mirror/OpenTTD
(svn r15027) -Merge: tomatos and bananas left to be, here is NoAI for all to see.
NoAI is an API (a framework) to build your own AIs in. See: http://wiki.openttd.org/wiki/index.php/AI:Main_Page With many thanks to: - glx and Rubidium for their syncing, feedback and hard work - Yexo for his feedback, patches, and AIs which tested the system very deep - Morloth for his feedback and patches - TJIP for hosting a challenge which kept NoAI on track - All AI authors for testing our AI API, and all other people who helped in one way or another -Remove: all old AIs and their cheats/hacks
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12
bin/ai/library/queue/fibonacci_heap/library.nut
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12
bin/ai/library/queue/fibonacci_heap/library.nut
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/* $Id$ */
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class FibonacciHeap extends AILibrary {
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function GetAuthor() { return "OpenTTD NoAI Developers Team"; }
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function GetName() { return "Fibonacci Heap"; }
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function GetDescription() { return "An implementation of a Fibonacci Heap"; }
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function GetVersion() { return 1; }
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function GetDate() { return "2008-08-22"; }
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function CreateInstance() { return "FibonacciHeap"; }
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}
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RegisterLibrary(FibonacciHeap());
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204
bin/ai/library/queue/fibonacci_heap/main.nut
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204
bin/ai/library/queue/fibonacci_heap/main.nut
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/* $Id$ */
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/**
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* Fibonacci heap.
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* This heap is heavily optimized for the Insert and Pop functions.
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* Peek and Pop always return the current lowest value in the list.
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* Insert is implemented as a lazy insert, as it will simply add the new
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* node to the root list. Sort is done on every Pop operation.
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*/
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class FibonacciHeap {
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_min = null;
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_min_index = 0;
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_min_priority = 0;
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_count = 0;
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_root_list = null;
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/**
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* Create a new fibonacci heap.
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* http://en.wikipedia.org/wiki/Fibonacci_heap
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*/
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constructor() {
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_count = 0;
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_min = Node();
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_min.priority = 0x7FFFFFFF;
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_min_index = 0;
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_min_priority = 0x7FFFFFFF;
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_root_list = [];
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}
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/**
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* Insert a new entry in the heap.
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* The complexity of this operation is O(1).
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* @param item The item to add to the list.
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* @param priority The priority this item has.
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*/
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function Insert(item, priority);
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/**
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* Pop the first entry of the list.
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* This is always the item with the lowest priority.
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* The complexity of this operation is O(ln n).
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* @return The item of the entry with the lowest priority.
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*/
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function Pop();
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/**
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* Peek the first entry of the list.
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* This is always the item with the lowest priority.
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* The complexity of this operation is O(1).
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* @return The item of the entry with the lowest priority.
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*/
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function Peek();
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/**
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* Get the amount of current items in the list.
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* The complexity of this operation is O(1).
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* @return The amount of items currently in the list.
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*/
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function Count();
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/**
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* Check if an item exists in the list.
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* The complexity of this operation is O(n).
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* @param item The item to check for.
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* @return True if the item is already in the list.
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*/
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function Exists(item);
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};
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function FibonacciHeap::Insert(item, priority) {
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/* Create a new node instance to add to the heap. */
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local node = Node();
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/* Changing params is faster than using constructor values */
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node.item = item;
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node.priority = priority;
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/* Update the reference to the minimum node if this node has a
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* smaller priority. */
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if (_min_priority > priority) {
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_min = node;
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_min_index = _root_list.len();
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_min_priority = priority;
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}
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_root_list.append(node);
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_count++;
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}
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function FibonacciHeap::Pop() {
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if (_count == 0) return null;
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/* Bring variables from the class scope to this scope explicitly to
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* optimize variable lookups by Squirrel. */
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local z = _min;
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local tmp_root_list = _root_list;
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/* If there are any children, bring them all to the root level. */
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tmp_root_list.extend(z.child);
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/* Remove the minimum node from the rootList. */
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tmp_root_list.remove(_min_index);
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local root_cache = {};
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/* Now we decrease the number of nodes on the root level by
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* merging nodes which have the same degree. The node with
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* the lowest priority value will become the parent. */
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foreach(x in tmp_root_list) {
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local y;
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/* See if we encountered a node with the same degree already. */
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while (y = root_cache.rawdelete(x.degree)) {
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/* Check the priorities. */
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if (x.priority > y.priority) {
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local tmp = x;
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x = y;
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y = tmp;
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}
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/* Make y a child of x. */
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x.child.append(y);
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x.degree++;
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}
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root_cache[x.degree] <- x;
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}
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/* The root_cache contains all the nodes which will form the
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* new rootList. We reset the priority to the maximum number
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* for a 32 signed integer to find a new minumum. */
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tmp_root_list.resize(root_cache.len());
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local i = 0;
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local tmp_min_priority = 0x7FFFFFFF;
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/* Now we need to find the new minimum among the root nodes. */
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foreach (val in root_cache) {
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if (val.priority < tmp_min_priority) {
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_min = val;
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_min_index = i;
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tmp_min_priority = val.priority;
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}
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tmp_root_list[i++] = val;
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}
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/* Update global variables. */
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_min_priority = tmp_min_priority;
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_count--;
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return z.item;
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}
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function FibonacciHeap::Peek() {
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if (_count == 0) return null;
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return _min.item;
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}
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function FibonacciHeap::Count() {
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return _count;
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}
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function FibonacciHeap::Exists(item) {
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return ExistsIn(_root_list, item);
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}
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/**
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* Auxilary function to search through the whole heap.
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* @param list The list of nodes to look through.
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* @param item The item to search for.
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* @return True if the item is found, false otherwise.
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*/
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function FibonacciHeap::ExistsIn(list, item) {
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foreach (val in list) {
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if (val.item == item) {
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return true;
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}
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foreach (c in val.child) {
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if (ExistsIn(c, item)) {
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return true;
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}
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}
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}
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/* No luck, item doesn't exists in the tree rooted under list. */
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return false;
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}
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/**
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* Basic class the fibonacci heap is composed of.
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*/
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class FibonacciHeap.Node {
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degree = null;
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child = null;
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item = null;
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priority = null;
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constructor() {
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child = [];
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degree = 0;
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}
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};
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