class Solution {
    public boolean isPopOrder(int[] pushV, int[] popV) {
        if (pushV.length != popV.length) {
            return false;
        }

        Deque<Integer> stack = new ArrayDeque<>();
        int popIndex = 0;
        for (int pushItem : pushV) {
            stack.push(pushItem);
            while(!stack.isEmpty() && stack.peek() == popV[popIndex]) {
                stack.pop();
                popIndex++;
            }
        }

        return stack.isEmpty();
    }
}