从零开始学数据结构与算法--4.链表

建立单个结点

/**
 * 连接点,相当于是车厢
 */
public class Node {
    //数据域
    public long data;
    //指针域
    public Node next;

    public Node(long value) {
        this.data = value;
    }

    /**
     * 显示方法
     */
    public void display() {
        System.out.println(data + "");
    }
}

建立链表,实际上就是创建一个火车头,指着下一辆

/**
 * 链表,相当于火车
 */
public class LinkList {
    //头结点
    private Node first;

    public LinkList() {
        first = null;
    }

    /**
     * 插入一个结点,在头结点后进行插入
     */
    public void insertFirst(long value) {
        Node node = new Node(value);
        if (first == null) {
            first = node;
        } else {
            node.next = first;
            first = node;
        }
    }

    /**
     * 删除一个结点,在头结点后进行删除
     */
    public Node deleteFirst() {
        Node tmp = first;
        first = tmp.next;
        return tmp;
    }

    /**
     * 显示方法
     */
    public void display() {
        Node current = first;
        while (current != null) {
            current.display();
            current = current.next;
        }
        System.out.println("***********");
    }

    /**
     * 查找方法
     */
    public Node find(long value) {
        Node current = first;
        while (current.data != value) {
            if (current.next == null) {
                return null;
            }
            current = current.next;
        }
        return current;
    }

    /**
     * 删除方法,根据数据域来进行删除
     */
    public Node delete(long value) {
        Node current = first;
        Node previous = first;
        while (current.data != value) {
            if (current.next == null) {
                return null;
            }
            previous =current;
            current = current.next;
        }
        if (current == first) {
            current = current.next;
        } else {
            previous.next = current.next;
        }
        return current;
    }
}

进行测试

 public static void main(String[] args) {
        LinkList linkList = new LinkList();
        linkList.insertFirst(34);
        linkList.insertFirst(23);
        linkList.insertFirst(12);
        linkList.insertFirst(0);
        linkList.insertFirst(-1);

//        linkList.display();
//        linkList.deleteFirst();
//        linkList.display();
//
//        Node node = linkList.find(23);
//        node.display();

        Node nodeDelete = linkList.delete(0);
        nodeDelete.display();
        System.out.println();
        linkList.display();
    }