Java實現(xiàn)雙鏈表的示例代碼
更新時間:2022年09月26日 09:10:37 作者:熬夜磕代碼丶
雙向鏈表也叫雙鏈表,是鏈表的一種,它的每個數(shù)據(jù)結點中都有兩個指針,分別指向直接后繼和直接前驅。本文將用Java語言實現(xiàn)雙鏈表,需要的可以參考一下
一、雙向鏈表是什么
雙向鏈表也叫雙鏈表,是鏈表的一種,它的每個數(shù)據(jù)結點中都有兩個指針,分別指向直接后繼和直接前驅。所以,從雙向鏈表中的任意一個結點開始,都可以很方便地訪問它的前驅結點和后繼結點。一般我們都構造雙向循環(huán)鏈表。
LinkedList底層就是一個雙向鏈表,我們來實現(xiàn)一個雙向鏈表。

這里多一個尾指針,方便我們對尾插操作從O(n)降到O(1).每個結點多了前驅結點,方便我們對鏈表進行操作。
二、具體方法實現(xiàn)
定義結點
class ListNode {
int value;
ListNode next;
ListNode prev;
public ListNode(int value) {
this.value = value;
}
}
下標訪問異常
public class IndexWrongException extends RuntimeException{
public IndexWrongException() {
}
public IndexWrongException(String message) {
super(message);
}
}
獲取鏈表長度
class ListNode {
int value;
ListNode next;
ListNode prev;
public ListNode(int value) {
this.value = value;
}
}
打印鏈表
class ListNode {
int value;
ListNode next;
ListNode prev;
public ListNode(int value) {
this.value = value;
}
}
清空鏈表
public void clear(){
if(this.head == null) {
return;
}
ListNode cur = this.head;
while(cur != null) {
ListNode curNext = cur.next;
cur.prev = null;
cur.next = null;
cur = curNext;
}
head = null;
tail = null;
}
頭插法
public void addFirst(int data){
ListNode node = new ListNode(data);
if(head == null) {
this.head = node;
this.tail = node;
return;
}
node.next = this.head;
this.head.prev = node;
this.head = node;
}
尾插法
public void addLast(int data){
ListNode node = new ListNode(data);
if(head == null) {
this.head = node;
this.tail = node;
return;
}
tail.next = node;
node.prev = tail;
tail = node;
}
指定位置插入
public void addIndex(int index,int data) throws IndexWrongException{
if(index < 0 || index > size()) {
throw new IndexWrongException("輸入下標不合法");
}
ListNode node = new ListNode(data);
if(index == 0) {
addFirst(data);
return;
}
if(index == size()) {
addLast(data);
return;
}
ListNode cur = this.head;
while(index != 0) {
cur = cur.next;
index--;
}
node.next = cur;
cur.prev.next = node;
node.prev = cur.prev;
cur.prev = node;
}查找元素
public boolean contains(int key){
if(head == null) {
return false;
}
ListNode cur = this.head;
while(cur != null) {
if(cur.value == key) {
return true;
}
cur = cur.next;
}
return false;
}
刪除第一次出現(xiàn)的關鍵字
public void remove(int key){
ListNode cur = head;
while(cur != head) {
if(cur.value == key) {
if(cur == head) {
head = head.next;
if(head.next != null) {
head.prev = null;
}else {
tail = null;
}
}else {
cur.prev.next = cur.next;
if(cur.next != null) {
cur.next.prev = cur.prev;
}else {
tail = cur.prev;
tail.next = null;
}
}
return;
}
cur = cur.next;
}
}刪除所有值為key的節(jié)點
public void removeAllKey(int key){
ListNode cur = head;
while(cur != head) {
if(cur.value == key) {
if(cur == head) {
head = head.next;
if(head.next != null) {
head.prev = null;
}else {
tail = null;
}
}else {
cur.prev.next = cur.next;
if(cur.next != null) {
cur.next.prev = cur.prev;
}else {
tail = cur.prev;
tail.next = null;
}
}
}
cur = cur.next;
}
}三、完整代碼
public class LinkedList {
static class ListNode {
int value;
ListNode next;
ListNode prev;
public ListNode(int value) {
this.value = value;
}
}
ListNode head;
ListNode tail;
//頭插法
public void addFirst(int data){
ListNode node = new ListNode(data);
if(head == null) {
this.head = node;
this.tail = node;
return;
}
node.next = this.head;
this.head.prev = node;
this.head = node;
}
//尾插法
public void addLast(int data){
ListNode node = new ListNode(data);
if(head == null) {
this.head = node;
this.tail = node;
return;
}
tail.next = node;
node.prev = tail;
tail = node;
}
//任意位置插入,第一個數(shù)據(jù)節(jié)點為0號下標
public void addIndex(int index,int data) throws IndexWrongException{
if(index < 0 || index > size()) {
throw new IndexWrongException("輸入下標不合法");
}
ListNode node = new ListNode(data);
if(index == 0) {
addFirst(data);
return;
}
if(index == size()) {
addLast(data);
return;
}
ListNode cur = this.head;
while(index != 0) {
cur = cur.next;
index--;
}
node.next = cur;
cur.prev.next = node;
node.prev = cur.prev;
cur.prev = node;
}
//查找是否包含關鍵字key是否在單鏈表當中
public boolean contains(int key){
if(head == null) {
return false;
}
ListNode cur = this.head;
while(cur != null) {
if(cur.value == key) {
return true;
}
cur = cur.next;
}
return false;
}
//刪除第一次出現(xiàn)關鍵字為key的節(jié)點
public void remove(int key){
ListNode cur = head;
while(cur != head) {
if(cur.value == key) {
if(cur == head) {
head = head.next;
if(head.next != null) {
head.prev = null;
}else {
tail = null;
}
}else {
cur.prev.next = cur.next;
if(cur.next != null) {
cur.next.prev = cur.prev;
}else {
tail = cur.prev;
tail.next = null;
}
}
return;
}
cur = cur.next;
}
}
//刪除所有值為key的節(jié)點
public void removeAllKey(int key){
ListNode cur = head;
while(cur != head) {
if(cur.value == key) {
if(cur == head) {
head = head.next;
if(head.next != null) {
head.prev = null;
}else {
tail = null;
}
}else {
cur.prev.next = cur.next;
if(cur.next != null) {
cur.next.prev = cur.prev;
}else {
tail = cur.prev;
tail.next = null;
}
}
}
cur = cur.next;
}
}
//得到單鏈表的長度
public int size(){
ListNode cur = head;
int count = 0;
while(cur != null) {
cur = cur.next;
count++;
}
return count;
}
public void display(){
ListNode cur = head;
while (cur != null) {
System.out.print(cur.value+" ");
cur = cur.next;
}
System.out.println();
}
public void clear(){
if(this.head == null) {
return;
}
ListNode cur = this.head;
while(cur != null) {
ListNode curNext = cur.next;
cur.prev = null;
cur.next = null;
cur = curNext;
}
head = null;
tail = null;
}
}
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