java--无头单向非循环链表

首先创建接口

public interface ILinked {
        //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);
        //关键字查找是否包含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3.3 链表面试题
        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();
    }

然后具体实现

public class MySingleList implements ILinked {

    class Node {
        public int getData() {
            return data;
        }

        private int data;

        public Node getNext() {
            return next;
        }

        public Node next;

        public Node(int data) {
            this.data = data;
            this.next = null;
        }
    }

    public Node getHead() {
        return head;
    }

    private Node head;

    public MySingleList() {
        this.head = null;
    }

    @Override
    public void addFirst(int data) {
        Node node = new Node(data);
        //第一次插入的时候，没有任何的数据节点
        if (this.head == null) {
            this.head = node;
        } else {
            node.next = this.head;
            this.head = node;
        }
    }

    @Override
    public void addLast(int data) {
        Node node = new Node(data);
        if (this.head == null) {
            this.head = node;
        } else {
            Node cur = this.head;
            while (cur.next != null) {
                cur = cur.next;
            }
            //cur所指向的位置就是尾节点
            cur.next = node;
        }

    }

    //检查index合法性
    private void checkIndex(int index) {
        if (index < 0 || index > getLength()) {
            throw new UnsupportedOperationException("Index不合法");
        }
    }

    //找到index-1的位置，函数返回该位置的节点引用
    private Node searchIndex(int index) {
        int count = 0;
        Node cur = this.head;
        while (count < index - 1) {
            cur = cur.next;
            count++;
        }
        return cur;
    }

    @Override
    public boolean addIndex(int index, int data) {
        checkIndex((index));
        //头插法
        if (index == 0) {
            addFirst(data);
            return true;
        } else {
            Node node = new Node(data);
            Node cur = searchIndex(index);
            node.next = cur.next;
            cur.next = node;

        }
        return true;
    }

    @Override
    public boolean contains(int key) {
        Node cur = this.head;
        /*if(this.head==null){
            return false;
        }*/
        while (cur != null) {
            if (cur.data == key) {
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    //查找关键字key的前驱
//如果找不到，返回null
    private Node searchPre(int key) {
        Node pre = this.head;
        //头结点是要删除的数据节点
        if (pre.data == key) {
            return this.head;
        }
        while (pre.next != null) {
            if (pre.next.data == key) {
                return pre;
            }
            pre = pre.next;
        }
        return null;
    }

    @Override
    public int remove(int key) {
        int oldData = 0;
        Node pre = searchPre(key);
        if (pre == null) {
            throw new UnsupportedOperationException("不存在key节点");
        }
        if (pre == head && pre.data == key) {
            oldData = this.head.data;
            this.head = this.head.next;
            return oldData;
        }
        Node del = pre.next;
        oldData = del.data;//先保存
        pre.next = del.next;//删除节点
        return oldData;
    }

    @Override
    public void removeAllKey(int key) {
        if (this.head == null) {
            return;
        }
        Node pre = this.head;
        Node cur = this.head.next;
        while (cur != null) {
            if (cur.data == key) {
                pre.next = cur.next;
                cur = cur.next;
            } else {
                pre = cur;
                cur = cur.next;
            }
        }
        if (this.head.data == key) {
            this.head = this.head.next;
        }
    }

    @Override
    public int getLength() {
        Node cur = this.head;
        int length = 0;
        while (cur != null) {
            cur = cur.next;
            length++;
        }
        return length;
    }

    @Override
    public void display() {
        Node cur = this.head;
        while (cur != null) {
            System.out.print(cur.data + " ");
            cur = cur.next;
        }
        System.out.println();
    }

    @Override
    public void clear() {
        Node cur = this.head;
        while (this.head != null) {
            this.head.next = null;
            this.head = cur;
            cur = cur.next;
        }

    }

测试类

public class Test2 {
    public static void main(String[] args) throws InterruptedException {
        MySingleList mySingleList = new MySingleList();
        /*mySingleList.addFirst(10);
        mySingleList.addFirst(20);
        mySingleList.addFirst(30);
        mySingleList.addFirst(40);
        mySingleList.addFirst(50);
        mySingleList.display();*/

       /* mySingleList.addLast(10);
        mySingleList.addFirst(88);
        mySingleList.addLast(20);
        mySingleList.addLast(30);
        mySingleList.addFirst(99);
        mySingleList.addLast(40);
        mySingleList.display();*/

        mySingleList.addIndex(0,10);
        mySingleList.addIndex(1,99);
        mySingleList.addIndex(2,20);
        mySingleList.addIndex(3,30);
        mySingleList.addIndex(4,88);
        mySingleList.addLast(40);
        mySingleList.addIndex(6,88);
        mySingleList.display();//10 99 20 30 88 40 98
        MySingleList.Node res = mySingleList.reverseList();
        mySingleList.show(res);
        /*mySingleList.show(mySingleList.reverseList());*/
 /*       System.out.println(mySingleList.contains(20));
        System.out.println(mySingleList.contains(21));*/
 /*       mySingleList.remove(10);
        mySingleList.display();//99 20 30 88 40 98*/
 /*     mySingleList.removeAllKey(88);
        mySingleList.display();
*/
        /*mySingleList.clear();*/
       /* Thread.sleep(1000);
        System.out.println("Hello bit");*/


       /* mySingleList.addFirst(10);
        mySingleList.addFirst(20);
        mySingleList.addFirst(30);
        mySingleList.addFirst(40);
        System.out.println(mySingleList.getLength());*/

       /*mySingleList.addLast(10);
       mySingleList.addLast(20);
       mySingleList.addLast(30);
       System.out.println(mySingleList.contains(20));
*/

       /* mySingleList.addFirst(10);
        mySingleList.addFirst(20);
        mySingleList.addFirst(30);
        mySingleList.addFirst(40);
        mySingleList.addFirst(50);
        mySingleList.clear();
        mySingleList.display();*/

   }


}