一.先上代码：
1.方式一：
public class LinkedList<E> {
//节点,用来存放数据：数据+下一个元素的引用
private class Node{
private E e;
private Node next;
public Node(E e,Node next){
this.e = e;
this.next = next;
}
public Node(E e){
this(e,null);
}
public Node(){
this(null,null);
}
public String toString(){
return e.toString();
}
}
private Node head;
private int size;
/**
* 构造方法
*/
public LinkedList(){
head = null;
size = 0;
}
/**
* 获取链表中元素的个数
* @return
*/
public int getSize(){
return size;
}
/**
* 判断链表是否为空
* @return
*/
public boolean isEmpty(){
return size == 0;
}
/**
* 链表头添加新元素
*/
public void addFirst(E e){
Node node = new Node();
node.next = head;
head = node;
size ++;
}
/**
* 链表中间添加元素
* @param index
* @param e
*/
public void add(int index,E e){
if (index < 0 || index > size){
throw new IllegalArgumentException("Add Failed");
}
if (index == 0){
addFirst(e);
}else {
Node prev = head;
for (int i = 0 ; i < index-1; i++){
prev = prev.next;
}
Node node = new Node(e);
node.next = new Node(e);
prev.next = node;
}
size++;
}
/**
* 链表末尾添加元素
* @param e
*/
public void addList(E e){
add(size,e);
}
}2.方式二：
public class LinkedListPlus<E> {
//节点,用来存放数据：数据+下一个元素的引用
private class Node{
private E e;
private Node next;
public Node(E e,Node next){
this.e = e;
this.next = next;
}
public Node(E e){
this(e,null);
}
public Node(){
this(null,null);
}
public String toString(){
return e.toString();
}
}
private Node dummyHead;//虚拟头节点
private int size;
public LinkedListPlus(){
dummyHead = new Node(null,null);
size = 0;
}
public int getSize(){
return size;
}
public boolean isEmpty(){
return size == 0;
}
public void add(int index,E e){
if (index < 0 || index > size){
throw new IllegalArgumentException("Add Failed");
}
Node prev = dummyHead;
for (int i = 0; i < index; i++) {
prev = prev.next;
}
Node node = new Node(e);
node.next = prev.next;
prev.next = node;
size++;
}
public void addFirst(E e){
add(0,e);
}
public void addLast(E e){
add(size,e);
}
public E get(int index){
if (index < 0 || index > size){
throw new IllegalArgumentException("Add Failed");
}
Node cur = dummyHead.next;
for (int i = 0; i <size ; i++) {
cur = cur.next;
}
return cur.e;
}
public E getFirst(){
return get(0);
}
public E getLast(){
return get(size-1);
}
public void set(int index,E e){
if (index < 0 || index > size){
throw new IllegalArgumentException("Add Failed");
}
Node cur = dummyHead.next;
for (int i = 0; i <size ; i++) {
cur = cur.next;
}
cur.e = e;
}
public boolean contains(E e){
Node cur = dummyHead.next;
while (cur != null){
if (cur.e.equals(e)){
return true;
}
cur = cur.next;
}
return false;
}
public E remove(int index){
if (index < 0 || index > size){
throw new IllegalArgumentException("Add Failed");
}
Node prev = dummyHead;
for (int i = 0; i <index ; i++) {
prev = prev.next;
}
Node retNode = prev.next;
prev.next = retNode.next;
retNode.next = null;
size--;
return retNode.e;
}
public E removeFirst(){
return remove(0);
}
public E removeLast(){
return remove(size-1);
}
@Override
public String toString() {
StringBuilder res = new StringBuilder();
Node cur = dummyHead.next;
while (cur != null){
res.append(cur+"->");
cur = cur.next;
}
res.append("null");
retu