双向链表
双向链表
相比单链表,节点多了一个pre指向前一个节点的地址
添加节点
思路
- 遍历方和单链表-样,只是可以向前,也可以向后查找
- 添加(默认添加到双向链表的最后)
- 先找到双向链表的最后这个节点
- temp.next =newHeroNode
- newHeroNode.pre =temp;
//添加一个节点(有序)
public void addByOrder(HeroNode2 heroNode2){
boolean flag = false;
HeroNode2 temp = head;
while (temp.next!=null){
if (temp.next.no>heroNode2.no){
break;
}else if (temp.next.no==heroNode2.no){
flag = true;
break;
}
temp=temp.next;
}
if (flag){
System.out.println("要添加的节点编号已存在");
}else {
if (temp.next!=null){
temp.next.pre = heroNode2;
heroNode2.next = temp.next;
}
temp.next = heroNode2;
heroNode2.pre = temp;
}
}
删除节点
- 删除
- 因为是双向链表,因此,我们可以实现自我删除某个节点
- 直接找到要删除的这个节点,比如temp
- temp.pre.next = temp.next
- temp.next.pre = temp.pre
//删除
public void del(int no){
if (head.next==null){
System.out.println("链表为空");
return;
}
HeroNode2 temp = head.next;
boolean flag = false;
while (temp!=null){
if (temp.no == no){
flag = true;
break;
}
temp = temp.next;
}
if (flag){
temp.pre.next = temp.next;
if (temp.next!=null){
temp.next.pre = temp.pre;
}
}
}
遍历双向链表
同单链表
public void list(){
if (head.next==null){
System.out.println("链表为空");
}
//头节点是空的,不需要遍历,所以temp直接指向temp.next,即第一个节点
HeroNode2 temp=head.next;
while (true){
if (temp==null){
break;
}
System.out.println(temp);
temp=temp.next;
}
}
修改双向链表节点信息
同单链表
//修改一个节点
public void update (HeroNode2 heroNode2){
if (heroNode2==null){
return;
}
boolean flag=false;//表示节点是否存在
HeroNode2 temp = head.next;
while (temp!=null){
if (temp.no == heroNode2.no ){
flag = true;
break;
}
if (temp.no > heroNode2.no){
break;
}
temp = temp.next;
}
if (flag){
temp.name = heroNode2.name;
temp.nickName = heroNode2.nickName;
}else {
System.out.println("你要修改的节点不存在");
}
}
代码实现(水浒英雄排行)
package Linked;
public class DoubleLinkedListDemo {
public static void main(String[] args) {
HeroNode2 hero1 = new HeroNode2(1, "松江", "及时雨");
HeroNode2 hero2 = new HeroNode2(2, "卢俊义", "玉麒麟");
HeroNode2 hero3 = new HeroNode2(3, "吴用", "智多星");
HeroNode2 hero4 = new HeroNode2(4, "林冲", "豹子头");
DoubleLinkedList doubleLinkedList = new DoubleLinkedList();
// doubleLinkedList.add(hero2);
// doubleLinkedList.add(hero3);
// doubleLinkedList.add(hero1);
// doubleLinkedList.add(hero4);
doubleLinkedList.addByOrder(hero2);
doubleLinkedList.addByOrder(hero3);
doubleLinkedList.addByOrder(hero1);
doubleLinkedList.addByOrder(hero4);
doubleLinkedList.list();
System.out.println("修改一个节点后");
HeroNode2 updateNode = new HeroNode2(4, "冲淋", "狮子头");
doubleLinkedList.update(updateNode);
doubleLinkedList.list();
System.out.println("删除一个节点后");
doubleLinkedList.del(1);
doubleLinkedList.list();
}
}
//创建一个双向链表
class DoubleLinkedList{
//创建一个空链表头
private HeroNode2 head=new HeroNode2(0,"","");
//返回head的节点
public HeroNode2 getHead() {
return head;
}
//遍历双向链表
public void list(){
if (head.next==null){
System.out.println("链表为空");
}
//头节点是空的,不需要遍历,所以temp直接指向temp.next,即第一个节点
HeroNode2 temp=head.next;
while (true){
if (temp==null){
break;
}
System.out.println(temp);
temp=temp.next;
}
}
//添加一个节点
public void add(HeroNode2 heroNode2){
HeroNode2 temp = head;
while (temp.next!=null){
temp = temp.next;
}
temp.next = heroNode2;
heroNode2.pre = temp;
}
//添加一个节点(有序)
public void addByOrder(HeroNode2 heroNode2){
boolean flag = false;
HeroNode2 temp = head;
while (temp.next!=null){
if (temp.next.no>heroNode2.no){
break;
}else if (temp.next.no==heroNode2.no){
flag = true;
break;
}
temp=temp.next;
}
if (flag){
System.out.println("要添加的节点编号已存在");
}else {
if (temp.next!=null){
temp.next.pre = heroNode2;
heroNode2.next = temp.next;
}
temp.next = heroNode2;
heroNode2.pre = temp;
}
}
//修改一个节点
public void update (HeroNode2 heroNode2){
if (heroNode2==null){
return;
}
boolean flag=false;//表示节点是否存在
HeroNode2 temp = head.next;
while (temp!=null){
if (temp.no == heroNode2.no ){
flag = true;
break;
}
if (temp.no > heroNode2.no){
break;
}
temp = temp.next;
}
if (flag){
temp.name = heroNode2.name;
temp.nickName = heroNode2.nickName;
}else {
System.out.println("你要修改的节点不存在");
}
}
//删除
public void del(int no){
if (head.next==null){
System.out.println("链表为空");
return;
}
HeroNode2 temp = head.next;
boolean flag = false;
while (temp!=null){
if (temp.no == no){
flag = true;
break;
}
temp = temp.next;
}
if (flag){
temp.pre.next = temp.next;
if (temp.next!=null){
temp.next.pre = temp.pre;
}
}
}
}
class HeroNode2{
public int no;
public String name;
public String nickName;
public HeroNode2 next;
public HeroNode2 pre;
public HeroNode2(int no, String name, String nickName) {
this.no = no;
this.name = name;
this.nickName = nickName;
}
@Override
public String toString() {
return "HeroNode2{" +
"no=" + no +
", name='" + name + '\'' +
", nickName='" + nickName + '\'' +
'}';
}
}