数据结构之模拟栈

不念不忘少年蓝@ 2023-01-01 08:00 132阅读 0赞

package com.qiangqiang.stack;
    
    public class Stack<T> {
        //采用链表来实现
        //记录首节点
        private Node node;
        private int size;
    
        /**
         * 保存单链表中的首节点
         */
        private Node headNode;
    
        /**
         * 保存单链表中的尾节点
         */
        private Node lastNode;
    
        //构造方法
        public Stack() {
            this.node = new Node(null, null);
            this.size = 0;
        }
    
        //判断当前栈中元素个数是否为0
        public boolean isEmpty() {
            return size == 0;
        }
    
    
        //获取栈中元素的个数
        public int size() {
            return this.size;
        }
    
        //压栈    //放在单链表的首节点
        public void push(T t) {
            //1.把需要添加的数封装成节点对象
            Node node = new Node(t, null);
            //2.处理单链表为空的情况
            if (headNode == null) {
                //2.1把node节点设置为单链表的首节点
                headNode = node;
                //2.2把node节点设置为单链表的尾节点
                lastNode = node;
            }
            //3.处理单链表不是空表的情况
            else {
                node.next = headNode;
                headNode = node;
    
            }
            //4.更新size的值
            size++;
        }
    
    
        //弹栈
        public T pop() {
            T item = headNode.item;
            headNode = headNode.next;
            size--;
            return item;
        }
    
    
        private class Node {
            private T item;
            private Node next;
    
            public Node(T item, Node next) {
                this.item = item;
                this.next = next;
            }
        }
    
        public static void main(String[] args) {
            Stack stack = new Stack();
            stack.push("11");
            stack.push("22");
    
            System.out.println();
            stack.pop();
            System.out.println();
        }
    }