说明：  快速排序是采用了递归的思想，首先找一个基准点（一般为第一个数），通过一次递归将要排序的数据分成两部分，其中一部分的所有数据比基准点小，另外一部分的所有数据都比基准点大，然后分别对两部分数据进行相同的处理，最后得到一个有序的数列。
(Quicksort is recursive to the idea, first of all to find a reference point (usually the first number), by the recursive data to be sorted into two parts, one part of all of the data is smaller than the reference point, and part of all data than the reference point and then separately on the two parts of the same data, and finally get an ordered sequence.)