题目

题解

import java.util.Stack;public class Solution {    Stack
    
      stack = new Stack();    Stack
     
       helpStack = new Stack();    public void push(int node) {        int helpStackTop = node;        if (!helpStack.isEmpty()) {            helpStackTop = Math.min(helpStack.peek(), helpStackTop);        }        stack.push(node);        helpStack.push(helpStackTop);    }        public void pop() {        if (stack.isEmpty()) {            return;        }        stack.pop();        helpStack.pop();    }        public int top() {        return stack.peek();    }        public int min() {        return helpStack.peek();    }}