题解 | #包含min函数的栈#

import java.util.Stack;

public class Solution {


    private Node head;

    /** initialize your data structure here. */
    public Solution() {
        head = new Node(0, Integer.MAX_VALUE, null);
    }

    public void push(int x) {
        // 头插法
        head = new Node(x, Math.min(x, head.min), head);
    }

    public void pop() {
        head = head.next;
    }

    public int top() {
        return head.val;
    }

    public int min() {
        // 获取头部最小值
        return head.min;
    }

    private class Node {
        // 存储的数据值
        public int val;
        // 最小值
        public int min;
        // 下一个节点
        public Node next;
        // 初始化
        public Node(int val, int min, Node next) {
            this.val = val;
            this.min = min;
            this.next = next;
        }
    }
}

解题思想：通过结点储存压入的数值，头插法最小结点在第一个。