数据结构及算法之链表讲解

1，普通实现方式

package com.dream21th.algorithmicdatastructure.linkedlist; /** * @Auther: hp * @Date: 2019/9/13 16:07 * @Description: */ public class LinkList { private class Node{ public E e; public 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); } @Override public String toString() { return e.toString(); } } private Node head; private int size; public LinkList() { this.head=null; size=0; } public int getSize(){ return size; } public boolean isEmpty(){ return size==0; } public void addFirst(E e){ /* Node node = new Node(e); node.next=head; head=node;*/ head = new Node(e, head); size++; } public void add(int index,E e){ if(index<0 || index>size){ throw new IllegalArgumentException("index is illegal"); } if(index==0){ addFirst(e); }else { Node prev=head; for(int i=0;i

2，带虚拟头节点实现方式

package com.dream21th.algorithmicdatastructure.linkedlist; /** * @Auther: hp * @Date: 2019/9/13 16:07 * @Description: */ public class LinkedList { private class Node{ public E e; public 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); } @Override public String toString() { return e.toString(); } } /** * 虚拟头节点 */ private Node dummyHead; private int size; public LinkedList() { this.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("index is illegal"); } Node prev=dummyHead; for(int i=0;i=size){ throw new IllegalArgumentException("index is illegal"); } Node cur=dummyHead.next; for(int i=0;i=size){ throw new IllegalArgumentException("index is illegal"); } Node cur=dummyHead.next; for(int i=0;i=size){ throw new IllegalArgumentException("index is illegal"); } Node prev=dummyHead; for(int i=0;i"); cur=cur.next; } builder.append("NULL"); return builder.toString(); } }