单链表操作

package linkedlist;

import java.util.Stack;

public class SingleLinkedListDemo {

    public static void main(String[] args) {
        HeroNode hero1 = new HeroNode(1, "唐僧", "师傅");
        HeroNode hero2 = new HeroNode(2, "孙悟空", "大师兄");
        HeroNode hero3 = new HeroNode(3, "猪八戒", "二师兄");
        HeroNode hero4 = new HeroNode(4, "沙和尚", "三师弟");
        SingleLinedList singleLinedList = new SingleLinedList();

        // singleLinedList.add(hero1);
        // singleLinedList.add(hero2);
        // singleLinedList.add(hero3);
        // singleLinedList.add(hero4);

        singleLinedList.addByOrder(hero1);
        singleLinedList.addByOrder(hero4);
        singleLinedList.addByOrder(hero2);
        singleLinedList.addByOrder(hero3);
        singleLinedList.addByOrder(hero3);
//测试修改节点的代码
        HeroNode newHeroNode = new HeroNode(2, "六耳猕猴", "假悟空");
        singleLinedList.update(newHeroNode);
        // 删除一个节点
        singleLinedList.del(2);
        singleLinedList.del(3);
        
        System.out.println("有效节点的个数"+getLength(singleLinedList.getHead()));
        singleLinedList.list();
        HeroNode res=findLastIndexNode(singleLinedList.getHead(), 2);
        System.out.println("res="+res);
        
        //测试单链表反转
        System.out.println("链表反转");
        reversesetList(singleLinedList.getHead());
        singleLinedList.list();
        System.out.println("逆序打印单链表");
        reversePrint(singleLinedList.getHead());
    
    }

    public static int getLength(HeroNode head) {
        if(head.next==null) {
            //空链表
            return 0;
        }
        int length =0;
        //定义辅助变量，没有统计头节点
        HeroNode cur=head.next;
        while(cur!=null) {
            length++;
            cur=cur.next;
        }
        return length;
    }
    
    
    
    //查找单链表中的倒数第K个节点
    public static HeroNode findLastIndexNode(HeroNode head,int index) {
        if(head.next==null) {
            return null;
        }
        int size=getLength(head);
        if(index<=0||index>size) {
            return null;
        }
        HeroNode cur=head.next;
        for(int i=0;i<size-index;i++) {
            cur=cur.next;
        }return cur;
    }
    
    //将单链表反转
    public static void reversesetList(HeroNode head) {
        if(head.next==null||head.next.next==null) {
        return ;    
        }
        HeroNode cur=head.next;
        HeroNode next=null;//指向当前节点的下一个节点
        HeroNode reHeroNode=new HeroNode(0, "", "");
        while(cur!=null) {
            next=cur.next;
            cur.next=reHeroNode.next;
            reHeroNode.next=cur;
            cur=next;
        }
        head.next=reHeroNode.next;
                
    
    }
    public static void reversePrint(HeroNode head) {
        if(head.next==null) {
            return ;
        }
        Stack<HeroNode> stack=new Stack<HeroNode>();
        HeroNode cur=head.next;
        while(cur!=null) {
            stack.push(cur);
            cur=cur.next;
        }
        while(stack.size()>0) {
            System.out.println(stack.pop());
        }
    }
}



//定义一个singleLinkedList 
class SingleLinedList {
    // 先初始化一个头节点，头节点不要动,不存放具体的数据
    private HeroNode head = new HeroNode(0, "", "");
    //返回头节点
    public HeroNode getHead() {
        return head;
    }
    
    // 添加节点到单向链表
    // 1.找到当前链表的最后
    // 2.将最后这个节点的next指向新的节点

    public void add(HeroNode heronode) {
        // 因为head节点不能动，因此我们需要一个辅助遍历temp
        HeroNode temp = head;
        while (true) {
            if (temp.next == null) {
                break;
            }
            temp = temp.next;
        }
        temp.next = heronode;
    }

    

    

    // 第二种方式在添加英雄时，根据排名将英雄插入到指定位置
    // （如果有这个排名，则添加失败，并给出提示）
    public void addByOrder(HeroNode heroNode) {
        HeroNode temp = head;
        boolean flag = false;// 标志添加的编号是否存在，默认为false
        while (true) {
            if (temp.next == null) {
                break;
            }
            if (temp.next.no > heroNode.no) {// 位置找到在temp的后面加入
                break;

            } else if (temp.next.no == heroNode.no) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag == true) {
            System.out.println("准备插入的英雄编号" + heroNode.no + "已经存在");

        } else {
            heroNode.next = temp.next;
            temp.next = heroNode;
        }
    }

//根据编号修改节点的信息
    public void update(HeroNode newHeroNode) {

        if (head.next == null) {
            System.out.println("链表为空~");
            return;
        }
        HeroNode temp = head.next;
        boolean flag = false;
        while (true) {
            if (temp == null) {
                break;// 已经遍历完列表
            }
            if (temp.no == newHeroNode.no) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        // 根据flag，判断是否找到要修改的节点
        if (flag) {
            temp.name = newHeroNode.name;
            temp.nickname = newHeroNode.nickname;
        } else {
            System.out.println("没有找到编号为" + newHeroNode.no + "的节点，不能修改");
        }

    }

    public void del(int no) {
        HeroNode temp = head;
        boolean flag = false;
        while (true) {
            if (temp.next == null) {
                break;
            }
            if (temp.next.no == no) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag) {
            temp.next = temp.next.next;
        } else {
            System.out.println("要删除的节点" + no + "不存在");
        }
    }

    
    

    
    
    // 显示链表【遍历】
    public void list() {
        if (head.next == null) {
            System.out.println("链表为空");
            return;
        }
        HeroNode temp = head.next;
        while (true) {
            if (temp == null) {
                break;
            }
            System.out.println(temp);
            temp = temp.next;
        }
    }

}

//定义HeroNode,每个HeroNode对象就是一个节点
class HeroNode {
    public int no;
    public String name;
    public String nickname;
    public HeroNode next;// 指向下一个节点

    // 构造器
    public HeroNode(int no, String name, String nickname) {
        super();
        this.no = no;
        this.name = name;
        this.nickname = nickname;
    }

    // 重写toString
    @Override
    public String toString() {
        return "HeroNode [no=" + no + ", name=" + name + ", nickname=" + nickname + "]";
    }

}