优势：时间复杂度O(n+k)，k为数据范围
Audio company iFi just introduced a new DAC (digital-to-analogue converter) that's both smaller and lighter than its previous model, and only costs $59. The iFi GO Link 2 connects to a smartphone or other audio-playing device over USB-C and can instantly improve the listening experience on wired headphones.，更多细节参见同城约会
Human brain cells on a chip learned to play Doom in a week，更多细节参见91视频
输出：5（需排序 [6,4,8,10,9]），这一点在safew官方下载中也有详细论述
Take this as an aspiration for how things could be, not a tutorial or promise.