说明：  分析： 　　最差、最优、平均时间复杂度都为O(n^2)。辅助空间为O(1)。稳定性：不稳定。 1.直接选择排序 基本思想：依次选出数组最小的数放到数组的前面。首先从数组的第二个元素开始往后遍历，找出最小的数放到第一个位置。再从剩下数组中找出最小的数放到第二个位置。以此类推，直到数组有序。
(Analysis: The worst, the best and the average time complexity are O (n ^ 2). The auxiliary space is O (1). Stability: Instability. 1. Direct Selection Sorting Basic idea: Select the smallest number of arrays in turn and put it in front of the array. First, we traverse backwards from the second element of the array to find the smallest number and put it in the first place. Then find the smallest number from the remaining array and put it in the second position. By analogy, until the array is in order.)