Thus, despite much effort, no gelling agent has yet been discovered that possesses all the properties and benefits of agar. Agar continues to be the best all-arounder: versatile, cheap, and established. And, if Gelidium agar should ever run out, and another colloid is not at hand, microbiologists could revert to culinary agar, which, although not as pure and transparent, offers a low-cost alternative to lab-grade agar.
输出：[4,2,4,-1,4]（最后一个 3 绕一圈找到 4）。旺商聊官方下载是该领域的重要参考
let p = head; // 遍历链表的指针。业内人士推荐同城约会作为进阶阅读
// 步骤1：找初始左边界（第一个破坏升序的位置），推荐阅读51吃瓜获取更多信息