Java LinkedList list

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LinkedList

LinkedList class extends AbstractSequentialList class and implements List interface;
LinkedList provides a connection list data structure;

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1. Constructor

Construction method	Explanation
LinkedList()	Create an empty list of links
LinkedList(Collection c)	Establishing a connection initiated by a list of elements c

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2. API

In addition to inheriting LinkedList List interface method, and provides the following methods:

Types of	method	Explanation
void	addFirst(Object o)	The collection begins with the insertion of the specified element
void	addLast(Object o)	Inserting the end of the collection specified element
Object	getFirst()	Returns the first element of the collection
Object	getLast()	Returns the last element of the collection
Object	removeFirst()	Removes and returns the first element of the collection
Object	removeLast()	Removes and returns the last element of the collection

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3. Use of class

• LinkedList additive element sequence and add () related order;
• LinkedList is not synchronized method, multiple threads access a List, must themselves implement access synchronization (ie thread safe);

import java.util.Iterator;
import java.util.LinkedList;

public class test {
    public static void main(String[] args) {
        LinkedList ll = new LinkedList();
        ll.add("apple");
        ll.add("banana");
        ll.addFirst("cat");
        ll.addLast("dog");
        Iterator it = ll.iterator();
        while (it.hasNext()) {
            System.out.print(it.next() + ", ");
        }
        System.out.println();
        System.out.println(ll.getFirst());
        System.out.println(ll.getLast());
        System.out.println(ll.removeFirst());
        System.out.println(ll.removeLast());
        ll.add(1, "ball");
        Object val = ll.get(2);
        ll.set(2, (String) val + " Updated");
        it = ll.iterator();
        while (it.hasNext()) {
            System.out.print(it.next() + ", ");
        }
    }
}
//输出：
//cat, apple, banana, dog, 
//cat
//dog
//cat
//dog
//apple, ball, banana Updated, 

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4. Comparison of the array

• An array is a contiguous memory space, fast query, add, and delete elements slow;
• Elements of the list are not stored in a row, the next element on a recording address of an element, deletions fast, slow query;