[数据结构与算法]算法与数据结构-简单实现LinkedList

public class test {
    public static void main(String[] args) {
        LinkedList<Character> linkedList = new LinkedList<>();
    }
}

class Node<E>{
    E item;
    Node<E> next;
    Node<E> prev;

    Node(Node<E> prev, E element, Node<E> next) {
        this.item = element;
        this.next = next;
        this.prev = prev;
    }
}

class LinkedList<E>{
    int size = 0;
    Node<E> first;// 第一个节点
    Node<E> last;// 最后一个节点

    // 判断是否回文串
    public boolean palindrome(LinkedList<E> list){
        Node<E> x = first;
        Node<E> y = last;
        int count = 1;
        while (count <= (size / 2)){
            if (x.item != y.item){
                return false;
            }
            x = x.next;
            y = y.prev;
            count++;
        }
        return true;
    }

    public void add (E e){
        Node<E> l = last;// 上一个节点，即当前链表中的最后一个节点
        Node<E> newNode = new Node<>(l, e, null);
        last = newNode;
        if (l == null){// 说明该节点是第一个
            first = newNode;
        }else {
            l.next = newNode;
        }
        size++;
    }

    // 删除链表中的第一个o
    public void remove(Object o){
        if (o == null){
            for (Node<E> x = first; x != null; x = x.next){
                if (x.item == null){
                    delete(x);
                }
            }
        }else {
            for (Node<E> x = first; x != null; x = x.next){
                if (o.equals(x.item)){
                    delete(x);
                }
            }
        }
    }

    public void delete(Node<E> x) {
        E element = x.item;
        Node<E> prev = x.prev;
        Node<E> next = x.next;

        if (prev == null){
            first = next;
        }else {
            prev.next = next;
            x.prev = null;
        }

        if (next == null){
            last = prev;
        }else {
            next.prev = prev;
            x.next = null;
        }

        x.item = null;
        size--;
    }

    public void print(){
        for (Node x = first; x != null; x = x.next){
            System.out.print(x.item + " ");
        }
        System.out.println();
    }
}