劍指Offer學習-面試題31:棧的壓入，彈出序列

	/**
     * 棧的壓入，彈出序列
     * 設置一個輔助棧，依次把彈出序列壓入輔助棧，如果輔助棧頂元素和原始棧棧頂元素相等，則都彈出
     * 最後棧爲空就說明彈出序列是棧的壓入序列
     *
     * @param pushOrder
     * @param popOrder
     * @return
     */
    public boolean isPopOrder(int[] pushOrder, int[] popOrder) {
        if (null == popOrder || null == popOrder || popOrder.length != pushOrder.length) return false;

        Stack<Integer> push_stack = new Stack<>();
        for (int i : pushOrder) {
            push_stack.push(i);
        }
        //輔助棧
        Stack<Integer> tmp_stack = new Stack<>();
        for (int i : popOrder) {
            tmp_stack.push(i);
            while (!tmp_stack.isEmpty() && !push_stack.isEmpty() && (tmp_stack.peek() == push_stack.peek())) {
                tmp_stack.pop();
                push_stack.pop();
            }
        }
        return push_stack.isEmpty();
    }