「java中的双链表类」java单链表和双链表的区别

今天给各位分享java中的双链表类的知识，其中也会对java单链表和双链表的区别进行解释，如果能碰巧解决你现在面临的问题，别忘了关注本站，现在开始吧！

本文目录一览：

• 1、在Java中如何实现双向链表?
• 2、在Java中如何实现双向链表
• 3、java中 双向链表是什么意思啊，是用来干啥的啊，求大神解答？谢谢

在Java中如何实现双向链表?

双向链表：就是有双向指针，即双向的链域。\x0d\x0a链结点的结构：\x0d\x0a┌────┬────┬────────┐\x0d\x0a│ data │ next │ previous │\x0d\x0a└────┴────┴────────┘\x0d\x0a双向链表不必是双端链表(持有对最后一个链结点的引用)，双端链表插入时是双向的。\x0d\x0a有两条链：一条从头到尾，一条从尾到头，删除遍历时也是双向的。\x0d\x0a/**\x0d\x0a * 双向链表\x0d\x0a */\x0d\x0apublic class DoublyLinkedList {\x0d\x0a private Link head; //首结点\x0d\x0a private Link rear; //尾部指针\x0d\x0a public DoublyLinkedList() { }\x0d\x0a public T peekHead() {\x0d\x0a if (head != null) {\x0d\x0a return head.data;\x0d\x0a }\x0d\x0a return null;\x0d\x0a }\x0d\x0a public boolean isEmpty() {\x0d\x0a return head == null;\x0d\x0a }\x0d\x0a public void insertFirst(T data) {// 插入 到 链头\x0d\x0a Link newLink = new Link(data);\x0d\x0a if (isEmpty()) {//为空时，第1次插入的新结点为尾结点\x0d\x0a rear = newLink;\x0d\x0a } else {\x0d\x0a head.previous = newLink; //旧头结点的上结点等于新结点\x0d\x0a }\x0d\x0a newLink.next = head; //新结点的下结点旧头结点\x0d\x0a head = newLink; //赋值后，头结点的下结点是旧头结点，上结点null\x0d\x0a }\x0d\x0a public void insertLast(T data) {//在链尾 插入\x0d\x0a Link newLink = new Link(data);\x0d\x0a if (isEmpty()) {\x0d\x0a head = newLink;\x0d\x0a } else {\x0d\x0a rear.next = newLink;\x0d\x0a }\x0d\x0a newLink.previous = rear;\x0d\x0a rear = newLink; //赋值后，尾结点的上结点是旧尾结点，下结点null\x0d\x0a }\x0d\x0a public T deleteHead() {//删除 链头\x0d\x0a if (isEmpty()) return null;\x0d\x0a Link temp = head;\x0d\x0a head = head.next; //变更首结点，为下一结点\x0d\x0a if (head != null) {\x0d\x0a head.previous = null;\x0d\x0a } else {\x0d\x0a rear = null;\x0d\x0a }\x0d\x0a return temp.data;\x0d\x0a }\x0d\x0a public T deleteRear() {//删除 链尾\x0d\x0a if (isEmpty()) return null;\x0d\x0a Link temp = rear;\x0d\x0a rear = rear.previous; //变更尾结点，为上一结点\x0d\x0a if (rear != null) {\x0d\x0a rear.next = null;\x0d\x0a } else {\x0d\x0a head = null;\x0d\x0a }\x0d\x0a return temp.data;\x0d\x0a }\x0d\x0a public T find(T t) {//从头到尾find\x0d\x0a if (isEmpty()) {\x0d\x0a return null;\x0d\x0a }\x0d\x0a Link find = head;\x0d\x0a while (find != null) {\x0d\x0a if (!find.data.equals(t)) {\x0d\x0a find = find.next;\x0d\x0a } else {\x0d\x0a break;\x0d\x0a }\x0d\x0a }\x0d\x0a if (find == null) {\x0d\x0a return null;\x0d\x0a }\x0d\x0a return find.data;\x0d\x0a }\x0d\x0a public T delete(T t) {\x0d\x0a if (isEmpty()) {\x0d\x0a return null;\x0d\x0a }\x0d\x0a Link current = head;\x0d\x0a while (!current.data.equals(t)) {\x0d\x0a current = current.next;\x0d\x0a if (current == null) {\x0d\x0a return null;\x0d\x0a }\x0d\x0a }\x0d\x0a if (current == head) {\x0d\x0a head = head.next;\x0d\x0a if (head != null) {\x0d\x0a head.previous = null;\x0d\x0a }\x0d\x0a } else if (current == rear) {\x0d\x0a rear = rear.previous;\x0d\x0a if (rear != null) {\x0d\x0a rear.next = null;\x0d\x0a }\x0d\x0a } else {\x0d\x0a //中间的非两端的结点，要移除current\x0d\x0a current.next.previous = current.previous;\x0d\x0a current.previous.next = current.next;\x0d\x0a }\x0d\x0a return current.data;\x0d\x0a }\x0d\x0a public boolean insertAfter(T key, T data) {//插入在key之后, key不存在return false\x0d\x0a if (isEmpty()) {\x0d\x0a return false;\x0d\x0a }\x0d\x0a Link current = head;\x0d\x0a while (!current.data.equals(key)) {\x0d\x0a current = current.next;\x0d\x0a if (current == null) {\x0d\x0a return false;\x0d\x0a }\x0d\x0a }\x0d\x0a Link newLink = new Link(data);\x0d\x0a if (current == rear) {\x0d\x0a rear = newLink;\x0d\x0a } else {\x0d\x0a newLink.next = current.next;\x0d\x0a current.next.previous = newLink;\x0d\x0a }\x0d\x0a current.next = newLink;\x0d\x0a newLink.previous = current;\x0d\x0a return true;\x0d\x0a }\x0d\x0a public void displayList4Head() {//从头开始遍历\x0d\x0a System.out.println("List (first--last):");\x0d\x0a Link current = head;\x0d\x0a while (current != null) {\x0d\x0a current.displayLink();\x0d\x0a current = current.next;\x0d\x0a }\x0d\x0a }\x0d\x0a public void displayList4Rear() {//从尾开始遍历\x0d\x0a System.out.println("List (last--first):");\x0d\x0a Link current = rear;\x0d\x0a while (current != null) {\x0d\x0a current.displayLink();\x0d\x0a current = current.previous;\x0d\x0a }\x0d\x0a }\x0d\x0a\x0d\x0a class Link {//链结点\x0d\x0a T data; //数据域\x0d\x0a Link next; //后继指针，结点 链域\x0d\x0a Link previous; //前驱指针，结点 链域\x0d\x0a Link(T data) {\x0d\x0a this.data = data;\x0d\x0a }\x0d\x0a void displayLink() {\x0d\x0a System.out.println("the data is " + data.toString());\x0d\x0a }\x0d\x0a }\x0d\x0a public static void main(String[] args) {\x0d\x0a DoublyLinkedList list = new DoublyLinkedList();\x0d\x0a list.insertLast(1);\x0d\x0a list.insertFirst(2);\x0d\x0a list.insertLast(3);\x0d\x0a list.insertFirst(4);\x0d\x0a list.insertLast(5);\x0d\x0a list.displayList4Head();\x0d\x0a Integer deleteHead = list.deleteHead();\x0d\x0a System.out.println("deleteHead:" + deleteHead);\x0d\x0a list.displayList4Head();\x0d\x0a Integer deleteRear = list.deleteRear();\x0d\x0a System.out.println("deleteRear:" + deleteRear);\x0d\x0a list.displayList4Rear();\x0d\x0a System.out.println("find:" + list.find(6));\x0d\x0a System.out.println("find:" + list.find(3));\x0d\x0a System.out.println("delete find:" + list.delete(6));\x0d\x0a System.out.println("delete find:" + list.delete(1));\x0d\x0a list.displayList4Head();\x0d\x0a System.out.println("----在指定key后插入----");\x0d\x0a list.insertAfter(2, 8);\x0d\x0a list.insertAfter(2, 9);\x0d\x0a list.insertAfter(9, 10);\x0d\x0a list.displayList4Head();\x0d\x0a }\x0d\x0a}

在Java中如何实现双向链表

双向链表：就是有双向指针，即双向的链域。

链结点的结构：

┌────┬────┬────────┐

│ data │ next │ previous │

└────┴────┴────────┘

双向链表不必是双端链表(持有对最后一个链结点的引用)，双端链表插入时是双向的。

有两条链：一条从头到尾，一条从尾到头，删除遍历时也是双向的。

/**

* 双向链表

*/

public class DoublyLinkedListt {

private Linkt head; //首结点

private Linkt rear; //尾部指针

public DoublyLinkedList() { }

public T peekHead() {

if (head != null) {

return head.data;

}

return null;

}

public boolean isEmpty() {

return head == null;

}

public void insertFirst(T data) {// 插入 到 链头

Linkt newLink = new Linkt(data);

if (isEmpty()) {//为空时，第1次插入的新结点为尾结点

rear = newLink;

} else {

head.previous = newLink; //旧头结点的上结点等于新结点

}

newLink.next = head; //新结点的下结点旧头结点

head = newLink; //赋值后，头结点的下结点是旧头结点，上结点null

}

public void insertLast(T data) {//在链尾 插入

Linkt newLink = new Linkt(data);

if (isEmpty()) {

head = newLink;

} else {

rear.next = newLink;

}

newLink.previous = rear;

rear = newLink; //赋值后，尾结点的上结点是旧尾结点，下结点null

}

public T deleteHead() {//删除 链头

if (isEmpty()) return null;

Linkt temp = head;

head = head.next; //变更首结点，为下一结点

if (head != null) {

head.previous = null;

} else {

rear = null;

}

return temp.data;

}

public T deleteRear() {//删除 链尾

if (isEmpty()) return null;

Linkt temp = rear;

rear = rear.previous; //变更尾结点，为上一结点

if (rear != null) {

rear.next = null;

} else {

head = null;

}

return temp.data;

}

public T find(T t) {//从头到尾find

if (isEmpty()) {

return null;

}

Linkt find = head;

while (find != null) {

if (!find.data.equals(t)) {

find = find.next;

} else {

break;

}

}

if (find == null) {

return null;

}

return find.data;

}

public T delete(T t) {

if (isEmpty()) {

return null;

}

Linkt current = head;

while (!current.data.equals(t)) {

current = current.next;

if (current == null) {

return null;

}

}

if (current == head) {

head = head.next;

if (head != null) {

head.previous = null;

}

} else if (current == rear) {

rear = rear.previous;

if (rear != null) {

rear.next = null;

}

} else {

//中间的非两端的结点，要移除current

current.next.previous = current.previous;

current.previous.next = current.next;

}

return current.data;

}

public boolean insertAfter(T key, T data) {//插入在key之后, key不存在return false

if (isEmpty()) {

return false;

}

Linkt current = head;

while (!current.data.equals(key)) {

current = current.next;

if (current == null) {

return false;

}

}

Linkt newLink = new Linkt(data);

if (current == rear) {

rear = newLink;

} else {

newLink.next = current.next;

current.next.previous = newLink;

}

current.next = newLink;

newLink.previous = current;

return true;

}

public void displayList4Head() {//从头开始遍历

System.out.println("List (first--last):");

Linkt current = head;

while (current != null) {

current.displayLink();

current = current.next;

}

}

public void displayList4Rear() {//从尾开始遍历

System.out.println("List (last--first):");

Linkt current = rear;

while (current != null) {

current.displayLink();

current = current.previous;

}

}

class Linkt {//链结点

T data; //数据域

Linkt next; //后继指针，结点 链域

Linkt previous; //前驱指针，结点 链域

Link(T data) {

this.data = data;

}

void displayLink() {

System.out.println("the data is " + data.toString());

}

}

public static void main(String[] args) {

DoublyLinkedListinteger list = new DoublyLinkedListinteger();

list.insertLast(1);

list.insertFirst(2);

list.insertLast(3);

list.insertFirst(4);

list.insertLast(5);

list.displayList4Head();

Integer deleteHead = list.deleteHead();

System.out.println("deleteHead:" + deleteHead);

list.displayList4Head();

Integer deleteRear = list.deleteRear();

System.out.println("deleteRear:" + deleteRear);

list.displayList4Rear();

System.out.println("find:" + list.find(6));

System.out.println("find:" + list.find(3));

System.out.println("delete find:" + list.delete(6));

System.out.println("delete find:" + list.delete(1));

list.displayList4Head();

System.out.println("----在指定key后插入----");

list.insertAfter(2, 8);

list.insertAfter(2, 9);

list.insertAfter(9, 10);

list.displayList4Head();

}

}

java中 双向链表是什么意思啊，是用来干啥的啊，求大神解答？谢谢

采用双向循环链表作为数据结构

1 新元素的下一个指向header

2 新元素的上一个指向header的上一个

3 新元素的上一个的下一个指向新元素

4 新元素的下一个的上一个指向新元素

一般LinkedList是采用双向循环链表，无需扩容，添加元素添加到最后即可

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