栈的push 、pop 序

题目：输入两个整数序列。其中一表示栈的 push 顺序，判断另一个序列有没可能是对应的 pop 顺序

package search;

import java.util.Stack;

public class PushPopSeries {
    public static boolean isPopSeries(int[] push,int[]  pop){
        if(push.length!=pop.length){
            return false;
        }
        int i1=0,i2=0,len=pop.length;
        Stack<Integer> stack=new Stack<Integer>();
        while(i2<len){
            while(stack.isEmpty()||stack.peek()!=pop[i2]){
                if(i1<len){
                    stack.push(push[i1++]);
                }else if(!stack.isEmpty()){
                    return false;
                }else{
                    break;
                }
                while(!stack.isEmpty()&&stack.peek()==pop[i2]){
                    stack.pop();
                    i2++;
                }
            }
        }
        return true;
    }
    public static void main(String args[]){
        int[] push={1,2,3,4,5};
        int[] pop={4,5,3,2,1};
        int[] pop2={4,3,5,1,2};
        System.out.println(PushPopSeries.isPopSeries(push, pop));
        System.out.println(PushPopSeries.isPopSeries(push, pop2));
    }
}