题解 | #包含min函数的栈#

import java.util.*;
import java.util.Stack;

public class Solution {
    Stack<Integer> stack1 = new Stack<>();
    Stack<Integer> stack2 = new Stack<>();

    public void push(int node) {
        stack1.push(node);
        if (stack2.isEmpty() || stack2.peek() >= node) {
            stack2.push(node);
             System.out.println("stack2新增"+stack2.peek());
        }
    }

    public void pop() {
       
        if (stack1.pop().equals(stack2.peek())) {
            System.out.println(stack2.peek());
            stack2.pop();
        }

    }

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

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

if (stack1.pop().equals(stack2.peek())) {
	System.out.println(stack2.peek());stack2.pop();
}

**用==运行出错，得用equals