算法通关村——手写栈

retgog

已于 2023-08-03 21:00:57 修改

阅读量162

点赞数

CC 4.0 BY-SA版权

文章标签：算法前端 javascript

于 2023-07-27 23:58:26 首次发布

本文链接：https://blog.youkuaiyun.com/retgog/article/details/131970822

该文章介绍了如何使用Java语言基于数组和链表两种数据结构实现栈。数组实现中，通过扩容方法处理栈满情况；链表实现中，通过节点操作完成压栈、出栈和查看栈顶元素。这两种方式都提供了isEmpty方法来检查栈是否为空。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

数组实现

import java.util.Arrays;

class MyStack<T> {
    private Object[] stack;
    private int top;

    MyStack(){
        stack = new Object[10];
    }

    public boolean isEmpty(){
        return top==0;
    }

    public void push(T t){
        expandCapacity(top+1);
        stack[top] = t;
        top++;
    }

    public T peek(){
        T t = null;
        if (top>0){
            t = (T)stack[top-1];
        }
        return t;
    }

    public T pop(){
        T t = peek();
        if (top>0){
            stack[top-1] = null;
            top--;
        }
        return t;
    }

    private void expandCapacity(int size) {
        int len = stack.length;
        if (size>len){
            size = size*3/2+1;
            stack = Arrays.copyOf(stack,size);
        }
    }
}

链表实现

class ListStack<T>{
    class Node<T>{
        public T t;
        public Node next;
    }

    public Node<T> head;

    ListStack(){
        head = null;
    }
    public void push(T t){
        if (t==null){
            throw new NullPointerException("参数不能为空");
        }
        if (head==null){
            head = new Node<T>();
            head.t = t;
            head.next = null;
        }else {
            Node<T> temp = head;
            head = new Node<>();
            head.t = t;
            head.next= temp;
        }
    }

    public T pop(){
        if (head==null){
            return null;
        }
        T t = head.t;
        head = head.next;
        return t;
    }

    public T peek(){
        if (head == null){
            return null;
        }
        T t = head.t;
        return t;
    }

    public boolean isEmpty(){
        if (head ==null){
            return true;
        }else {
            return false;
        }
    }
}