題目描述
定義棧的資料結構，請在該型別中實現一個能夠得到棧最小元素的min函式。

import java.util.Stack;

public class Solution {

    Stack<Integer> stack1 = new Stack<Integer>();
    Stack<Integer> stack2 = new Stack<Integer>();


    public void push(int node) {

        if (stack2.empty()){
            stack2.push(node);
        }else
 
 {
            int top1 = stack1.peek();
            if (top1 >= node){
                stack2.push(node);
            }else {
                stack2.push(top1);
            }
        }
        stack1.push(node);
    }

    public void pop() {
        stack2.pop();
        stack1.pop();

    }

    public
 
 int top() {
        return stack1.peek();

    }

    public int min() {
        return stack2.peek();
    }
}