/**

 *

 */

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));

    }

}