Java.util.PriorityQueue类

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📜 Java.util.PriorityQueue类

📅 最后修改于: 2020-11-14 06:20:45 🧑 作者: Mango

介绍

java.util.PriorityQueue类是一个基于优先级堆的无界优先级队列。以下是PriorityQueue的重点-

以下是java.util.PriorityQueue类的声明-

public class PriorityQueue
   extends AbstractQueue
   implements Serializable

以下是java.util.PriorityQueue类的参数-

E-这是此集合中包含的元素的类型。

Sr.No.	Constructor & Description
1	PriorityQueue() This creates a PriorityQueue with the default initial capacity (11) that orders its elements according to their natural ordering.
2	PriorityQueue(Collection c) This creates a PriorityQueue containing the elements in the specified collection.
3	PriorityQueue(int initialCapacity) This creates a PriorityQueue with the specified initial capacity that orders its elements according to their natural ordering.
4	PriorityQueue(int initialCapacity, Comparator comparator) This creates a PriorityQueue with the specified initial capacity that orders its elements according to the specified comparator.
5	PriorityQueue(PriorityQueue c) This creates a PriorityQueue containing the elements in the specified priority queue.
6	PriorityQueue(SortedSet c) This creates a PriorityQueue containing the elements in the specified sorted set.

Sr.No.	Method & Description
1	boolean add(E e) This method inserts the specified element into this priority queue.
2	void clear() This method removes all of the elements from this priority queue.
3	Comparator comparator() This method returns the comparator used to order the elements in this queue, or null if this queue is sorted according to the natural ordering of its elements.
4	boolean contains(Object o) This method returns true if this queue contains the specified element.
5	Iterator iterator() This method returns an iterator over the elements in this queue.
6	boolean offer(E e) This method inserts the specified element into this priority queue.
7	E peek() This method retrieves, but does not remove, the head of this queue, or returns null if this queue is empty.
8	E poll() This method retrieves and removes the head of this queue, or returns null if this queue is empty.
9	boolean remove(Object o) This method removes a single instance of the specified element from this queue, if it is present.
10	int size() This method returns the number of elements in this collection.
11	Object[] toArray() This method returns an array containing all of the elements in this queue.
12	T[] toArray(T[] a) This method returns an array containing all of the elements in this queue; the runtime type of the returned array is that of the specified array.

此类从以下类继承方法-