问题描述：输入若干组长度各异的待排序列，分别用快速排序算法和改进的枢轴元素三者取中算法对待排序列进行排序，当待排子序列长度已小于 20时，改用直接插入排序，利用时间函数验证三者取中算法在效率上的提高。（提示： 待排序列的长度一般应为 5000 以上）-Problem Descr iption: Enter the number of head of the column to be sorted varying degrees, respectively, with quick sort algorithm and improved algorithm pivotal element in the treatment of the three to take to sort the column sorting, row when the sequence length has to be less than 20, the switch direct insertion sort, using a function of time to take in the three validation algorithms to improve efficiency. (Hint: The length of the column to be sorted should generally be more than 5000)