接口方法:
public interface ICLinked {
//头插法
void addFirst(int data);
//尾插法
void addLast(int data);
//任意位置插入,第一个数据节点为0号下标
boolean addindex(int index,int data);
//查找是否包含关键字key是否在单链表当中
boolean contains(int key);
//删除第一次出现关键字为key的节点
int remove(int key);
//删除所有值为key的节点
void removeAllKey(int key);
//得到单链表的长度
int getLength();
void display();
void clear();
}
实现接口及方法重写:
public class HeadSingleLinkedListImpl implements ICLinked {
class Node{
private int data;
private Node next;
//头结点
public Node(){
this.data = -1;
}
//数据节点
public Node (int data){
this.data = data;
}
}
private Node head;
public HeadSingleLinkedListImpl() {
this.head = new Node();
this.head.next = this.head;
}
@Override
public void addFirst(int data) {
Node node = new Node(data);
node.next = this.head.next;
this.head.next = node;
}
@Override
public void addLast(int data) {
Node cur = this.head;
while (cur.next != this.head){
cur = cur.next;
}
Node node = new Node(data);
node.next = cur.next;
cur.next = node;
}
//找到index-1的位置
private Node searchIndex(int index){
checkIndex(index);
Node cur = this.head;
for (int i = 0; i < index; i++) {
cur = cur.next;
}
return cur;
}
private void checkIndex(int index){
if (index < 0 || index > getLength()){
throw new UnsupportedOperationException("index不合法");
}
}
@Override
public boolean addindex(int index, int data) {
Node pre = searchIndex(index);
Node node = new Node(data);
node.next = pre.next;
pre.next = node;
return true;
}
@Override
public boolean contains(int key) {
Node cur = this.head;
Node node = new Node(key);
if (head.data == key){
cur = cur.next;
}
return false;
}
private Node SearchPre(int key){
Node pre = this.head;
while (pre.next != this.head){
if(pre.next.data == key){
return pre;
}
pre = pre.next;
}
return null;
}
@Override
public int remove(int key) {
Node pre = SearchPre(key);
if (pre == null){
throw new UnsupportedOperationException("key不存在");
}
Node del = pre.next;
int oldData = pre.data;
pre.next = del.next;
return oldData;
}
@Override
public void removeAllKey(int key) {
Node pre = this.head;
Node cur = this.head.next;
while (cur != this.head){
if(cur.data == key){
pre.next = cur.next;
cur = pre.next;
}
pre = cur;
cur =cur.next;
}
}
@Override
public int getLength() {
int length = 0;
Node cur = this.head.next;
while (cur != this.head) {
length++;
cur = cur.next;
}
return length;
}
@Override
public void display() {
Node cur = this.head.next;
while (cur != head){
System.out.print(cur.data+" ");
cur = cur.next;
}
System.out.println();
}
@Override
public void clear() {
while (head.next != head){
Node cur = this.head.next;
head.next = cur.next;
cur = cur.next;
}
}
}
测试用例:
public class TestMain {
public static void main(String[] args) {
HeadSingleLinkedListImpl headSingleList = new HeadSingleLinkedListImpl();
headSingleList.addFirst(10);
headSingleList.addFirst(20);
headSingleList.display();
headSingleList.addLast(40);
headSingleList.addLast(10);
headSingleList.addLast(50);
headSingleList.display();
headSingleList.addindex(2,100);
headSingleList.addindex(3,200);
headSingleList.display();
headSingleList.remove(200);
headSingleList.display();
headSingleList.removeAllKey(10);
headSingleList.display();
System.out.println(headSingleList.getLength());
headSingleList.clear();
headSingleList.display();
}
}