单链表之CRUD操作

Posted 2021-09-25 程序彤

package 链表.单链表crud;

public class SingleLinkedListDemo {
    public static void main(String[] args) {
        SingleLinkedList sll = new SingleLinkedList();
        HeroNode heroNode1 = new HeroNode(1, "虚空掠夺者");
        HeroNode heroNode2 = new HeroNode(2, "风暴之怒");
        HeroNode heroNode3 = new HeroNode(3, "盖伦");
        HeroNode heroNode4 = new HeroNode(4, "寒冰");

        sll.add(heroNode2);
        sll.add(heroNode3);
        sll.add(heroNode1);
        sll.add(heroNode4);

        sll.update(new HeroNode(3,"德玛西亚"));
        sll.del(4);
        sll.query();
    }
}

class HeroNode {
    public int id;
    public String name;
    public HeroNode next;

    public HeroNode(int id, String name) {
        this.id = id;
        this.name = name;
    }

    @Override
    public String toString() {
        return "HeroNode{" +
                "id=" + id +
                ", name='" + name + '\\'' +
                '}';
    }
}

class SingleLinkedList {
    public HeroNode head = new HeroNode(0, "");

    // 增
    public void add(HeroNode heroNode) {
        HeroNode curr = head;
        boolean isRepeated = false;
        while (true) {
            if (curr.next == null) { // 在末尾也可以去加
                break;
            }
            if (curr.next.id > heroNode.id) { // 找到则退出循环去加
                break;
            }
            if (curr.next.id == heroNode.id) {
                isRepeated = true;
                break;
            }
            curr = curr.next;
        }
        // 为了防止添加重复节点，这里做判断
        if (isRepeated) {
            System.out.printf("英雄编号%d已重复，不可重复添加~", heroNode.id);
        }
        heroNode.next = curr.next; // 这样写
        curr.next = heroNode;

//        curr.next = heroNode; // 这样写 则改变了当前节点的下一个节点
//        heroNode.next = curr.next;
    }

    // 删
    public void del(int id) {
        HeroNode curr = head;
        boolean isExist = true;
        while (true) {
            if (curr.next == null) { // 特殊情况处理
                isExist = false;
                break;
            }
            if (curr.next.id == id) { // 满足情况退出
                break;
            }
            curr = curr.next;
        }
        if (!isExist) {
            System.out.printf("英雄编号%d不存在，没有可以删除的~", id);
        }
        curr.next = curr.next.next;
    }

    // 改
    public void update(HeroNode heroNode) {
        HeroNode curr = head;
        boolean isExist = true;
        while (true) {
            if (curr.next == null) { // 特殊情况处理
                isExist = false;
                break;
            }
            if (curr.next.id == heroNode.id) { // 满足情况退出
                break;
            }
            curr = curr.next;
        }
        if (!isExist) {
            System.out.printf("英雄编号%d不存在，没有可以修改的",heroNode.id);
        }
        curr.next.name = heroNode.name;
    }

    // 查
    public void query(){
        if (head.next == null) {
            return;
        }
        HeroNode curr = head.next;
        while (true) {
            if (curr == null) { // 到链表最后一个的下一个即为null
                break;
            }
            System.out.println(curr);
            curr = curr.next;
        }
    }
}