java双向链表操作
双向链表的每一个结点都有一条指向其后继结点的next指针和一条指向其前结点的pre指针。
双向链表的插入图示：
双向链表的删除图示：
import java.io.IOException;
import java.util.Scanner;
class Node{
public int data;//数据域
public Node next;//后继指针域
public Node previous;//前驱指针域
public Node(int data) {
this.data = data;
this.next = null;
this.previous = null;
}
//显示该结点的数据
public void display() {
System.out.print( data + " ");
}
}
public class Main {
public static Node head = null;//表头
public static int length = 0;
//在链表头部添加结点
public static void addHead(int data) {
Node newNode = new Node(data);
if(head == null) {
head = newNode;//如果链表为空，增加新结点
}
else {
newNode.next = head;
head.previous = newNode;
head = newNode;
}
length++;
}
//在链表头部删除结点
public static void deleteHead() {
if(head == null){
System.out.println("空表，删除的结点不存在");
}
else {
Node curNode = head;
head = curNode.next;
head.previous = null;
}
length--;
}
//在链表尾部添加结点
public static void addTail(int data) {
Node newNode = new Node(data);
if (head == null) {
head = newNode;
} else {
Node curNode = head;
int count = 1;
while (count < length) {
curNode = curNode.next;
count++;
}
newNode.next = null;
newNode.previous = curNode;
curNode.next = newNode;
}
length++;
}
//在链表尾部删除结点
public static void deleteTail() {
if(head == null){
System.out.println("空表，删除的结点不存在");
}else{
Node preNode = head;
int count = 1;
while(count < length-1) {
preNode = preNode.next;
count++;
}
preNode.next = null;
}
length--;
}
//正向遍历链表
public static void printOrderNode() {
if(head == null) {
System.out.println("空表");
}
Node curNode = head;
while (curNode != null) {
curNode.display();
curNode = curNode.next;
}
System.out.println();
}
//反向遍历链表
public static void printReverseNode() {
if(head == null) {
System.out.println("空表");
}
Node curNode = head;
while (curNode.next != null) {
curNode = curNode.next;
}
while (curNode != null) {
curNode.display();
curNode = curNode.previous;
}
System.out.println();
}
//在指定位置插入结点
public static void insertList(int data, int index) {
Node newNode = new Node(data);
if(head == null){
head = newNode;//链表为空，插入
}
if(index > length+1 || index < 1) {
System.out.println("结点插入的位置不存在，可插入的位置为1到"+(length+1));
}
if(index == 1) {
newNode.next = head;
head.previous = newNode;
head = newNode;//在链表开头插入
} else{ //在链表中间或尾部插入
Node preNode = head;
int count = 1;
while(count < index-1) {
preNode = preNode.next;
count++;
}
Node curNode = preNode.next;
newNode.next = curNode;
newNode.previous = preNode;
preNode.next = newNode;
if(curNode != null) {
curNode.previous = newNode;
}
}
length++;
}
//在指定位置删除结点
public static void deleteList(int index) {
if(index > length || index < 1) {
System.out.println("结点删除的位置不存在，可删除的位置为1到"+length);
}
if(index == 1) {
Node curNode = head;
head = curNode.next;
head.previous = null;
length--;
} else{
Node preNode = head;
int count = 1;
while(count < index-1) {
preNode = preNode.next;
count++;
}
Node curNode = preNode.next;
Node laterNode = curNode.next;
preNode.next = laterNode;
if(laterNode != null) { //若被删除结点的后继结点不是null结点，那么设置其前驱结点
laterNode.previous = preNode;//指针指向被删除结点的前驱结点
}
length--;
}
}
//查找数据是否存在,与单链表一样
public static boolean containData(int data) {
if(head == null){
System.out.println("空表");
return false;
}
Node curNode = head;
while(curNode.data!= data){
if(curNode.next == null) {
System.out.println("结点数据不存在");
return false;
}
curNode =curNode.next;
}
System.out.println("结点数据存在");
return true;
}
//获取指定位置的数据，与单链表一样
public static void getIndexData(int index) {
if(head == null){
System.out.println("空表");
}
if(index > length || index < 1) {
System.out.println("结点位置不存在，可获取的位置为1到"+length);
}
Node curNode = head;
int count =1;
while(count != index) {
curNode =curNode.next;
count++;
}
curNode.display();
System.out.println();
}
//修改指定位置的结点数据，与单链表一样
public static void updateIndexData(int index, int data) {
if(head == null){
System.out.println("空表");
}
if(index > length || index < 1) {
System.out.println("结点位置不存在，可更新的位置为1到"+length);
}
Node curNode = head;
int count =1;//while也可以用for循环方式解决
while(count != index) {
curNode =curNode.next;
count++;
}
curNode.data = data;
}
//打印链表
public static void printList(){
Node tmp = head;
while(tmp != null){
System.out.print(tmp.data + " ");
tmp = tmp.next;
}
System.out.println();
}
public static void main(String []args) throws IOException {
Scanner sc = new Scanner(System.in);
while (true) {
int s = sc.nextInt();
if(s == 0) {
break;
}else {
addHead(s);
}
}
//输入样例
//1
//2
//3
//0 输入0结束
printList();
deleteHead();
printList();
printOrderNode();
Scanner in = new Scanner(System.in);
int index = sc.nextInt();
int data = sc.nextInt();
insertList(data, index);
printList();
}
}