1. 找出最大数，确定最大位数d
// 注意：slice(0, 负数)会返回空字符串，需兼容（比如stack长度<k时，slice后为空）
。旺商聊官方下载对此有专业解读
周鸿祎回应三六零发力AI眼镜：“这东西挺难做的”
FirstFT: the day's biggest stories
"Cloning streams in Node.js's fetch() implementation is harder than it looks. When you clone a request or response body, you're calling tee() - which splits a single stream into two branches that both need to be consumed. If one consumer reads faster than the other, data buffers unbounded in memory waiting for the slow branch. If you don't properly consume both branches, the underlying connection leaks. The coordination required between two readers sharing one source makes it easy to accidentally break the original request or exhaust connection pools. It's a simple API call with complex underlying mechanics that are difficult to get right." - Matteo Collina, Ph.D. - Platformatic Co-Founder & CTO, Node.js Technical Steering Committee Chair