Stack栈常用操作方法

Stack

import java.util.Stack;

/*
先进后出
 */
public class _Stack {
    public static void main(String[] args) {
        //创建栈
        Stack<Integer> stack= new Stack<>();
        //添加元素，时间复杂度：O(1)
        stack.push(1);
        stack.push(2);
        stack.push(3);
        stack.push(4);
        //[1, 2, 3, 4]
        System.out.println(stack.toString());

        //获取栈顶元素，时间复杂度：O(1)
        int p = stack.peek();
        //4
        System.out.println(p);

        //移除栈顶元素，时间复杂度：O(1)
        int temp = stack.pop();
        //4
        System.out.println(temp);
        //获取栈长度，时间复杂度：O(1)
        //3
        System.out.println(stack.size());
        //判断栈是否为空，时间复杂度：O(1)
        System.out.println(stack.empty());//false

        //迭代栈，时间复杂度：O(N)
        while(!stack.isEmpty()){
            int num = stack.pop();

            System.out.println(num);
        }
    }
}