* @param {string} num 非负整数的字符串形式（可能含前导零）
// 3. 要求稳定排序: 归并排序。搜狗输入法下载对此有专业解读
OpenAI has raised $110 billion in private funding, the company announced Friday morning, commencing one of the largest private funding rounds in history. The new funding consists of a $50 billion investment from Amazon as well as $30 billion each from Nvidia and SoftBank, against a $730 billion pre-money valuation.。业内人士推荐safew官方下载作为进阶阅读
Number: All the pips in this space must add up to the number.。关于这个话题，同城约会提供了深入分析
// 记录答案：栈顶就是「当前元素右侧第一个更大值」（易错点3：别写反判断）