Java實現單鏈表的增刪改查

package algorithm.linkedlist;

/**
 * @Created by XDarker
 * @Description Java實現單鏈表的增刪改查
 * @Date 2019/10/12 22:22
 */
public class LinkedListDemo {

    public static void main(String[] args) {

//        HeroNode node1 = new HeroNode("A");
//        HeroNode node2 = new HeroNode("B");
//        HeroNode node3 = new HeroNode("C");
//        HeroNode node4 = new HeroNode("D");
//
//        SingleLinkedList singleLinkedList = new SingleLinkedList();
//        singleLinkedList.add(node1);
//        singleLinkedList.add(node2);
//        singleLinkedList.add(node3);
//        singleLinkedList.add(node4);


        HeroNode node1 = new HeroNode(1,"A");
        HeroNode node2 = new HeroNode(3,"B");
        HeroNode node3 = new HeroNode(5,"C");
        HeroNode node4 = new HeroNode(7,"D");

        SingleLinkedList singleLinkedList = new SingleLinkedList();
        singleLinkedList.addByNum(node1);
        singleLinkedList.addByNum(node4);
        singleLinkedList.addByNum(node2);
        singleLinkedList.addByNum(node3);
        singleLinkedList.list();

        HeroNode newHeroNode = new HeroNode(3,"BBB");
        singleLinkedList.update(newHeroNode);

        System.out.println("==========修改之後==========");
        singleLinkedList.list();

        System.out.println("==========刪除之後==========");
        singleLinkedList.delete(newHeroNode);
        singleLinkedList.list();

    }

}

class SingleLinkedList{

    //初始化頭節點
    private HeroNode head = new HeroNode("");


    /**
     * 添加鏈表節點
     * @param heroNode
     */
    public void add(HeroNode heroNode){

        HeroNode temp = head;
        //遍歷鏈表， 找到最後
        while(true){
            if (temp.next == null){
                break;
            }
            temp = temp.next;
        }
        //退出循環時 temp指向了鏈表的最後
        temp.next = heroNode;
    }

    /**
     * 根據排位添加鏈表節點
     * 如果排位已經存在則添加失敗
     * @param heroNode
     */
    public void addByNum(HeroNode heroNode){

        HeroNode temp = head;
        //標誌添加的編號是否存在 默認false
        boolean flag = false;
        while (true){
            //說明temp已經到鏈表最後
            if (temp.next == null){
                break;
            }
            //位置找到， 在temp後加入
            if (temp.next.num > heroNode.num){
                break;
             //說明排位已經存在
            }else if(temp.next.num == heroNode.num){
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag){
            System.out.printf("添加的鏈表排位 %d 已經存在, 不能加入\n", heroNode.num);
        }else {
            heroNode.next = temp.next;
            temp.next = heroNode;
        }
    }

    /**
     * 根據 num 修改節點
     * @param newHeroNode
     */
    public void update(HeroNode newHeroNode){

        if (head.next == null){
            System.out.println("鏈表爲空");
            return;
        }
        HeroNode temp = head;
        //表示是否找到該節點
        boolean flag = false;
        while(true){
            //說明temp已經到鏈表最後
            if (temp.next == null){
                break;
            }
            if (temp.num == newHeroNode.num){
                //找到
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag){
            temp.name = newHeroNode.name;
        }else {
            System.out.printf("該排位 %d 的節點不存在\n", newHeroNode.num);
        }


    }

    /**
     * 根據 num 刪除節點
     * @param heroNode
     */
    public void delete(HeroNode heroNode){

        if (head.next == null){
            System.out.println("鏈表爲空");
        }

        HeroNode temp = head;
        boolean flag = false;
        while (true){
            if (temp.next == null){
                break;
            }
            if (temp.next.num == heroNode.num){
                flag = true;
                break;
            }
            temp = temp.next;
        }

        if (flag){
            temp.next = temp.next.next;
        }else {
            System.out.printf("要刪除的排位 %d 的節點不存在", heroNode.num);
        }

    }

    /**
     * 顯示鏈表
     */
    public void list(){
        if (head.next == null){
            System.out.println("鏈表爲空");
        }
        HeroNode temp = head.next;
        while (true){
            if (temp == null){
                break;
            }
            System.out.println(temp);
            temp = temp.next;
        }

    }


}



class HeroNode {

    public String name;
    public Integer num;
    public HeroNode next;  //指向下一個節點
    //構造器
    public HeroNode(String name){
        this.name = name;
    }

    public HeroNode(Integer num, String name){
        this.num = num;
        this.name = name;
    };

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