带头节点的双链表及其基本操作（Java实现）

亦凉 2022-06-07 04:48 210阅读 0赞

package lwh.linearlist.linklist;
    
    public class DbNode {
    
        protected int e;
        protected DbNode next;
        protected DbNode previous;
    
        public DbNode(){}
    
        public DbNode(int e){
            this.e = e;
        }
    
        public int getE() {
            return e;
        }
        public void setE(int e) {
            this.e = e;
        }
        public DbNode getNext() {
            return next;
        }
        public void setNext(DbNode next) {
            this.next = next;
        }
        public DbNode getPrevious() {
            return previous;
        }
        public void setPrevious(DbNode previous) {
            this.previous = previous;
        }
    }

package lwh.linearlist.linklist;
    
    //带头节点的双链表
    public class DbLinkedList {
    
        private DbNode head;
    
        public DbLinkedList(){
            head = new DbNode();
            head.next = null;
            head.previous = null;
        }
    
        //在头节点后面插入节点
        public void insertHead(int num){
            DbNode node = new DbNode(num);
            DbNode p = head.next;
            if(p != null){
                node.next = p;
                p.previous = node;
                node.previous = head;
                head.next = node;
            }else{
                head.next = node;
                node.previous = head;
            }
        }
    
        //求表长,不包括表头节点
        public int length(){
            int len = 0;
            DbNode p = head.next;
            while(p != null){
                len++;
                p = p.next;
            }
            return len;
        }
    
        //删除i处的节点
        public boolean delete(int i){
            if(i < 1 || i > length()){
                System.out.println("Delete index wrong");
                return false;
            }
            DbNode q = head.next;
            int j = 1;
            while(j < i){
                q = q.next;
                j++;
            }
            DbNode r = q.next;
            DbNode p = q.previous;
            if(r != null){
                p.next = r;
                r.previous = p;
                q = null;
            }else{
                p.next = null;
                q = null;
            }
            return true;
        }
    
        public void print() {
            if(head.next == null){
                System.out.println("No num");
                return;
            }
            System.out.print("[");
            for(DbNode node = head.next; node != null; node = node.next){
                if(node.next != null)
                    System.out.print(node.e + ",");
                else
                    System.out.print(node.e + "]");
            }
            System.out.println();
        }
    }