通过精心挑选划分元素v，可以得到一个最坏情况时间复杂度为O(n)的选择算法。本次实习要求用c语言将此算法实现。要求实现此功能：输入一组数，返回A[i],使其为A(m:p)中第k小的元素，k是一个全局变量，取大于1的整数-division through carefully selected elements v, one can be the worst time complexity of O (n) algorithm. The internship requirement c language used this algorithm. Calls for this function : the importation of a number of groups, the return of A [i], so A (m : p) k small elements, k is a global variables, from an integer greater than