priority-queue

问题 I wanted to implement multiprocessing priorityqueue . I found this answer :- Strange Queue.PriorityQueue behaviour with multiprocessing in Python 2.7.6 by Dano After I implemented this . I could use .get() and .put() function for my Priority Queue but when i used .queue to print the current elements in the queue it gave me an error code:- class MyManager(SyncManager): pass def get_manager(): MyManager.register("PriorityQueue", PriorityQueue) # Register a shared PriorityQueue m = MyManager() m

问题 public class PriorityQueue<T> { private PriorityNode<T> head, tail; private int numItems; public PriorityQueue(){ numItems = 0; head=null; tail=null; } public void add(int priority, T value){ PriorityNode<T> newNode = new PriorityNode<T>(priority,value); if(numItems == 0){ head = newNode; tail = newNode; } else{ head.setNext(newNode); head = newNode; } } } Where PriorityNode is defined as: public class PriorityNode<T> implements Comparable<T> { private T value; private PriorityNode<T> next;

问题 I read that priority queue is an abstract data type for heap data structure or to put it in another way, heap is an implementation for priority queues. But what confuses me is that I see heap in itself as an ADT since they're normally implemented using arrays (talking about min/max heaps here). Could someone give me a clear distinction among the three within the realm of ADT? 回答1: Let me answer you in two steps.. i) Defenitions Data type is a set of values together with operations on that

问题 It seems I'm missing something very simple: what are advantages of a Binary Heap for a Priority Queue comparing, say, with quick-sorted array of values? In both cases we keep values in an array, insert is O(logN), delete-max is O(1) in both cases. Initial construction out of a given array of elements is O(NlogN) in both cases, though the link http://en.wikipedia.org/wiki/Heap_%28data_structure%29 suggests faster Floyd's algorithm for the Binary Heap construction. But in case of a queue the

问题 Priority receive in Erlang can easily be implemented as follows: prio() -> receive {priority, X} -> X after 0 -> receive X -> X end end. I am reading a paper called Priority Messaging made Easy in which they describe the following problem: The main problem with the [code] example [above], is that we do not take into consideration that when evaluation is resumed from the inner blocking receive we may have more than one message in the mailbox. In a worst case scenario, all but the first, of

问题 How can I remove the tail element of a priority queue? I am trying to implement beam search using a priority queue and once the priority queue is full, I want to remove the last element(the element with the least priority). Thanks! 回答1: No easy way. Copy elements from original to new except the last. PriorityQueue removelast(PriorityQueue pq) { PriorityQueue pqnew; while(pq.size() > 1) { pqnew.add(pq.poll()); } pq.clear(); return pqnew; } called as pq = removelast(pq); 回答2: You could probably

问题 As you know from the title, I'm trying to use PriorityQueue with multiprocessing. More precisely, I wanted to make shared PriorityQueue, wrote some code and it doesn't run as I expected. Look at the code: import time from multiprocessing import Process, Lock from Queue import PriorityQueue def worker(queue): lock = Lock() with lock: for i in range(100): queue.put(i) print "worker", queue.qsize() pr_queue = PriorityQueue() worker_process = Process(target = worker, args = (pr_queue,)) worker

问题 I have a college programming project in C++ divided into two parts. I beggining the second part where it's supposed to use priority_queues , hash tables and BST 's. I'm having trouble (at least) with priority queues since it's obligating myself to redone a lot of code already implemented in the first part. The project it's about implementing a simple airport management system and, therefore, I have classes like Airport (main class), Airplane, Terminal and Flight. My airport had a list of

问题 I have implemented a priority queue using a linked list. In this priority queue the smallest int value has the highest value and therefore by calling the remove method the smallest method will be removed. Code for Node Class public class Node { public int iData; public Node next; public Node(int x) { iData = x; } public void displayNode() { System.out.println(iData + " "); } } Code for Link List public class LinkList { private Node first; public LinkList() { first = null; } public boolean

问题 This question already has answers here : The built-in iterator for java's PriorityQueue does not traverse the data structure in any particular order. Why? (5 answers) Closed 5 years ago . I was trying to insert the integers in PriorityQueue , and I know that : If no comparator is specified when a PriorityQueue is constructed, then the default comparator for the type of data stored in the queue is used. The default comparator will order the queue in ascending order However, the output I am