package cn.hxd.collection;
/*** 创建一个节点类* @author Administrator**/
public class Node {Node previous;Object object;Node next;public Node() {}public Node(Node privious, Object object, Node next) {super();this.previous = privious;this.object = object;this.next = next;}public Node getPrivious() {return previous;}public void setPrivious(Node privious) {this.previous = privious;}public Object getObject() {return object;}public void setObject(Object object) {this.object = object;}public Node getNext() {return next;}public void setNext(Node next) {this.next = next;}}

package cn.hxd.collection;
/*** 自己实现的Linkedlist* @author Administrator**/
public class MyLinkedList {private Node first;private Node last;private int size;public void add(Object obj) {//在末尾添加元素Node n = new Node();if(first==null) {n.setPrivious(null);n.setObject(obj);n.setNext(null);first = n;last = n;}else {n.setPrivious(last);n.setObject(obj);n.setNext(null);last.setNext(n);last = n;}size++;}public void add(int index,Object obj) {//在指定位置添加元素Node temp = node(index);Node newNode = new Node();newNode.object = obj;if(index==0) {//指定第一个位置添加元素first = newNode;temp.previous = newNode;newNode.next = temp;size++;}else if(index ==size) {//指定最后一个位置添加元素add(obj);}else {Node up = temp.previous;up.next = newNode;newNode.previous = up;newNode.next = temp;temp.previous = newNode;size++;}}public int size() {//返回列表大小return size;}public Object get(int index) {//返回指定位置的对象rangeCheck(index);Node temp = node(index);if(temp!=null) {return temp.object;}return null;}private void rangeCheck(int index) {if(index<0||index>=size) {try {throw new Exception();} catch (Exception e) {e.printStackTrace();}}}public void remove(int index){//删除指定位置的对象元素Node temp = node(index);if(index==0) {temp.next.previous = null;first = temp.next;}else if(temp.next==null) {last = temp.previous;}else {Node up = temp.previous;Node down = temp.next;up.next = down;down.previous = up;}
//      if(temp!=null&&index != 0&&index!=size-1){
//          Node up = temp.previous;
//          Node down = temp.next;
//          up.next = down;
//          down.previous = up;
//      }else if(index==0) {
//          temp.next.previous = null;
//          first = temp.next;
//      }else if(temp.next==null) {
//          last = temp.previous;
//      }size--; }public void clear() {}public Node node(int index) {//返回指定位置的对象元素Node temp = null;if(first!=null) {if(index<(size>>1)) {temp = first;for(int i=0;i<index;i++) {temp = temp.next;}}else {temp = last;for(int i=size-1;i>index;i--) {temp = temp.previous;}}}return temp;}public static void main(String[] args) {MyLinkedList list= new MyLinkedList();list.add("aaa");list.add("bbb");list.add("ccc");//list.add(0,"000");//list.add(3, 333);//list.remove(2);System.out.println(list.size);System.out.println(list.get(3));for(int i=0;i<list.size;i++) {System.out.print(list.get(i)+" ");}}
}