Java（16）LinkedList

package list;

import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;


public class MyLinkedList implements List {
    private int size;
    private Node first;
    private Node last;

    private static class Node {
        // 存储的数据
        Object item;
        // 上一个
        Node next;
        // 下一个
        Node prev;

        public Node(Node prev, Object item, Node next) {
            this.next = next;
            this.item = item;
            this.prev = prev;
        }
    }

    @Override
    public int size() {
        return size;
    }

    @Override
    public boolean isEmpty() {
        return false;
    }

    @Override
    public boolean contains(Object o) {
        return false;
    }

    @Override
    public Iterator iterator() {
        return null;
    }

    @Override
    public Object[] toArray() {
        return new Object[0];
    }

    @Override
    public boolean add(Object o) {
        Node l = last;
        Node node = new Node(l, o, null);
        last = node;
        if (l == null) {
            first = node;
        } else {
            l.next = node;
        }
        size++;
        return true;
    }

    @Override
    public boolean remove(Object o) {
        return false;
    }

    @Override
    public boolean addAll(Collection c) {
        return false;
    }

    @Override
    public boolean addAll(int index, Collection c) {
        return false;
    }

    @Override
    public void clear() {

    }

    @Override
    public Object get(int index) {
        if (index < (size >> 1)) {
            Node x = first;
            for (int i = 0; i < index; i++) {
                x = x.next;
            }
            return x.item;
        } else {
            Node x = last;
            for (int i = size - 1; i > index; i--) {
                x = x.prev;
            }
            return x.item;
        }
    }

    @Override
    public Object set(int index, Object element) {
        return null;
    }

    @Override
    public void add(int index, Object element) {

    }

    @Override
    public Object remove(int index) {
        return null;
    }

    @Override
    public int indexOf(Object o) {
        return 0;
    }

    @Override
    public int lastIndexOf(Object o) {
        return 0;
    }

    @Override
    public ListIterator listIterator() {
        return null;
    }

    @Override
    public ListIterator listIterator(int index) {
        return null;
    }

    @Override
    public List subList(int fromIndex, int toIndex) {
        return null;
    }

    @Override
    public boolean retainAll(Collection c) {
        return false;
    }

    @Override
    public boolean removeAll(Collection c) {
        return false;
    }

    @Override
    public boolean containsAll(Collection c) {
        return false;
    }

    @Override
    public Object[] toArray(Object[] a) {
        return new Object[0];
    }
}

package Test.list;

import list.MyArrayList;
import list.MyLinkedList;
import org.junit.jupiter.api.Test;

import java.util.List;

public class MylinkedListTest {
    @Test
    public void test01() {
        List list = new MyLinkedList();
        for (int i = 0; i < 5; i++) {
            list.add(i);
        }
        System.out.println(list.size());
    }
//5
    @Test
    public void test02() {
        List list = new MyLinkedList();
        for (int i = 0; i < 10; i++) {
            list.add(i);
        }
        System.out.println(list.size());
    }
//10
    @Test
    public void test03() {
        List list = new MyLinkedList();
        for (int i = 0; i < 10; i++) {
            list.add(i);
        }
        System.out.println(list.size());
        list.add(10);
        System.out.println(list.size());
    }

    @Test
    public void test04() {
        List list = new MyLinkedList();
        for (int i = 0; i < 10; i++) {
            list.add(i);
        }
        System.out.println(list.size());
        list.add(10);
        System.out.println(list.size());
        System.out.println(list.get(5));
    }

    @Test
    public void test05() {
        List list = new MyLinkedList();
        for (int i = 0; i < 10; i++) {
            list.add(i);
        }
        for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
        }
    }

    @Test
    public void test06() {
        List list = new MyArrayList();
        for (int i = 0; i < 10; i++) {
            list.add(i);
        }
        System.out.println(list);
    }
//[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    @Test
    public void test07() {
        List list = new MyArrayList();
        for (int i = 0; i < 10; i++) {
            list.add(i);
        }
        System.out.println(list);
        list.remove(3);
        System.out.println(list);
        System.out.println(list.size());
    }

}