栈的压入弹出序列

public class Solution {
    public boolean IsPopOrder(int [] pushA,int [] popA) {
        Stack<Integer> stack = new Stack<>();
        int popJ = 0; // 指向pop数组的被比较元素
        for(int i=0;i<pushA.length;i++){
            stack.push(pushA[i]);
            if(pushA[i] == popA[popJ]){
                stack.pop(); // 弹出栈顶元素
                popJ++;
            }
        }
        
        while(!stack.isEmpty()){
            if(stack.peek() == popA[popJ++]){
                stack.pop();
            }else {
                return false;
            }
        }
        return true;
    }
}