栈的压入、弹出序列

import java.util.Stack;

public class Solution {
    public boolean IsPopOrder(int [] pushA,int [] popA) {

        if(pushA.length==0||popA.length==0)
        {
             return false;
        }
        Stack<Integer>stack=new Stack<>(); //开启的辅助栈
        int popIndex=0;
        for(int i=0;i<pushA.length;i++)
        { 
            stack.push(pushA[i]);  //压入辅助栈
            while(!stack.isEmpty()&&stack.peek()==popA[popIndex])
            {
                 stack.pop();
                 ++popIndex;
            }

        }

        return stack.isEmpty();
    }
    public static void main(String[]args){

        int[]pushA={1,2,3,4,5};
        int[]pushA2={1};
        int[]popA={4,5,3,2,1};
        int[]popA2={4,3,5,1,2};
        Solution s=new Solution();
        System.out.println(s.IsPopOrder(pushA,popA));
        System.out.println(s.IsPopOrder(pushA,popA2));
    }
}