/**
* Created by peter on 2017/2/22.
*/
public class LinkedList {
private Node head,tail;
private int size=0;
public void add(Object o){
Node node = new Node();
node.data = o;
node.next=null;
if(size==0){
head=node;
tail=node;
}else{
tail.next = node;
tail = tail.next;
}
size++;
}
public void add(int index,Object o){
if(index<0||index>size){
System.out.println("插入下标越界");
throw new ArrayIndexOutOfBoundsException();
}
//如果插入的位置是第一个
if(index==0){
Node node =new Node();
node.data = o;
node.next = head;
head = node;
}else {
int i =0;//记录走过的节点
Node p = head;//移动节点
while (i<index-1){
p=p.next;
i++;
}
//寻找到要插入位置的上一个位置
Node node = new Node();
node.data=o;
node.next=p.next;
p.next=node;
}
size++;
}
public Object get(int index){
if(index<0||index>size-1){
System.out.println("访问下标越界");
throw new ArrayIndexOutOfBoundsException();
}
Node node =head;
int i=0;
while (i<index){
node=node.next;
i++;
}
return node.data;
}
public Object remove(int index){
//如果链表里没有数据则不能删除
if(size==0){
System.out.println("list is empty");
}
if(index<0||index>size-1){
System.out.println("out of array");
throw new ArrayIndexOutOfBoundsException();
}
Object data=null;//用来存储返回值
if(index==0){
//删除的是第一个节点
data = head.data;
head=head.next;
size--;
return data;
}else{
Node p1=head,p2=null;//p1表示移动节点，p2是上一个节点
int i =0;//表示移动的距离
while (i<index){
p2=p1;
p1=p1.next;
i++;
}
data = p1.data;
if(index==size-1){
p2.next = null;
tail = p2;
}else{
p2.next = p1.next;
}
size--;
return data;
}
}
public int size(){
return size;
}
public void addFirst(Object o){
add(0,o);
}
public Object removeFirst(){
return remove(0);
}
public Object removeLast() {
return remove(size-1);
}
//内部节点类
static class Node{
public Object data;
public Node next;
}
}