链表基本操作

文章目录

public class  Node{
       int data;
        Node next;
      public Node(int data){
          this.data=data;
      }
    }

    Node  head=null;
    public void create(){
        head = new Node(0);
        head.next=null;
    }
    public boolean insert(Node a ){//在末尾插入
        if(head == null){
            return false;
        }
        if(head.next == null){
            head.next=a;
            a.next=null;
            return true;
        }
        Node p = head.next;
        Node q =p.next;
        while (q!=null){
            p=q;
            q=q.next;
        }
        p.next=a;
        a.next=null;
        return true;
    }
    public boolean insert(int index,Node a){//在第index的后面插入a
        if(head == null){
            return false;
        }
        if(head.next==null){
            return false;
        }
        int count=1;
        Node p= head.next;
        Node q=p.next;
        while (count<index&&q!=null){
            count++;
            p=q;
            q=q.next;
        }
        if(count!=index){
            return false;
        }
        p.next=a;
        a.next=q;
        return true;
    }
    public boolean delete(int index){//删除第index个后面的那个元素
        if(head == null){
            return false;
        }
        if(head.next==null){
            return false;
        }
        int count=1;
        Node p= head.next;
        Node q=p.next;
        while (count<index&&q!=null){
            count++;
            p=q;
            q=q.next;
        }
        if(count!=index){
            return false;
        }
        p.next=q.next;
        return true;
    }