java单链表基本操作

/**
 *
 */
package cn.com.wwh;

/**
 * @Description:TODO
 * @author:wwh
 * @time:2021-1-18 19:24:47
 */
public class SingleLinkedList <T>{

    Node list;//头结点
    int size;//节点个数

    public class Node{
        T data;
        Node next;

        public Node(T data,Node next) {
            this.data = data;
            this.next = next;
        }
    }

    /**
     *
     * @Description:头部增加节点
     * @param data
     * @return
     * @author: wwh
     * @time:2021-1-18 19:27:24
     */
    public void add(T data) {
        Node node = new Node(data, list);
        list = node;
        size++;
    }

    /**
     *
     * @Description:指定位置增加结点
     * @param data
     * @param index
     * @return
     * @author: wwh
     * @time:2021-1-18 19:28:51
     */
    public void add(T data,int index) {
        checkIndex(index);
        if (index == 0) {
            add(data);
            return;
        }else {
            Node preNode = list;
            Node curNode = list;
            for (int i = 0; i < index; i++) {
                preNode = curNode;
                curNode = curNode.next;
            }
            Node node = new Node(data, curNode);
            preNode.next = node;
            size++;
        }
    }

    /**
     *
     * @Description:删除头部结点
     * @return
     * @author: wwh
     * @time:2021-1-18 19:33:51
     */
    public T remove() {
        if (list != null) {
            Node headNode = list;
            list = list.next;
            headNode.next = null;//GC
            size--;
            return headNode.data;
        }
        return null;
    }

    /**
     *
     * @Description:删除指定位置的结点
     * @param index
     * @return
     * @return
     * @author: wwh
     * @time:2021-1-18 19:35:49
     */
    public T remove(int index) {
        checkIndex(index);
        if (list != null) {
            if (index == 0) {
                return remove();
            }
            Node preNode = list;
            Node curNode = list;
            for (int i = 0; i < index; i++) {
                preNode = curNode;
                curNode = curNode.next;
            }
            preNode.next = curNode.next;
            curNode.next = null;
            size--;
            return curNode.data;
        }
        return null;
    }

    /**
     *
     * @Description:删除最后一个结点
     * @return
     * @return
     * @author: wwh
     * @time:2021-1-18 19:38:42
     */
    public T removeLast() {
        if (list != null) {
            Node preNode = list;
            Node curNode = list;
            while (curNode.next != null) {
                preNode = curNode;
                curNode = curNode.next;
            }
            preNode.next = null;
            size--;
            return curNode.data;
        }
        return null;
    }

    /**
     *
     * @Description:修改指定位置的值
     * @param index
     * @param data
     * @return
     * @author: wwh
     * @time:2021-1-18 19:41:23
     */
    public void set(int index,T data) {
        checkIndex(index);
        Node curNode = list;
        for (int i = 0; i < index; i++) {
            curNode = curNode.next;
        }
        curNode.data = data;
    }

    /**
     *
     * @Description:获取头结点
     * @return
     * @return
     * @author: wwh
     * @time:2021-1-18 19:42:48
     */
    public T get() {
        if (list != null) {
            return list.data;
        }
        return null;
    }

    /**
     *
     * @Description:获取指定位置的结点
     * @param index
     * @return
     * @return
     * @author: wwh
     * @time:2021-1-18 19:44:06
     */
    public T get(int index) {
        checkIndex(index);
        if (list != null) {
            Node curNode = list;
            for (int i = 0; i < index; i++) {
                curNode = curNode.next;
            }
            return curNode.data;
        }
        return null;
    }

    /**
     *
     * @Description:下标检查
     * @param index
     * @return
     * @author: wwh
     * @time:2021-1-18 19:29:24
     */
    public void checkIndex(int index) {
        if (!(index >= 0 && index <= size)) {
            throw new IndexOutOfBoundsException(index +": out of " + size );
        }
    }

    @Override
    public String toString() {
        Node node = list;
        for (int i = 0; i < size; i++) {
            System.err.print(node.data + " ");
            node = node.next;
        }
        System.err.println();
        return super.toString();
    }

    public static void main(String[] args) {
        SingleLinkedList list1 = new SingleLinkedList();
        for (int i = 0; i < 5; i++) {
            list1.add(i);
        }
        list1.toString();
        list1.add(3);
        list1.toString();
        list1.add(34, 6);
        list1.toString();
        list1.remove();
        list1.toString();
        list1.removeLast();
        list1.toString();
        list1.remove(0);
        list1.toString();
        list1.set(0, 88);
        list1.toString();
        System.err.println(list1.get());
        System.err.println(list1.get(3));
    }
}