/*
            *学生互换，本质上是求N个数组的数据平衡问题，使每个数组的平均分于平均分差值小于0.5
            */
            for (int i = 0; i < stuClass.Count; i++)
            {
                List<StudentDetail> stu1 = stuClass[i];
                int index = getindex(i, avg,avgCj);//要交换的b[x]中的索引数
                //如果avgCj[i]-avg<+_0.5的时候，index返回值为99，不进行交换；否则返回avgCj[i]中的索引值，stuClass[i]与stuClass[index]的值进行交换
                if (index != 99)
                {
                    List<StudentDetail> stu2 = stuClass[index];
                    StudentDetail temp =new StudentDetail();
                    for(int j =0;j<stu1.Count;j++){
                        for (int k = 0; k < stu2.Count;k++ )
                        {
                            while((avgCj[i] - avg) > 0.5)
                            {
                                if (stu1[j].StudengCj > stu2[k].StudengCj) {
                                    temp = stu1[j];
                                    stu1[j]=stu2[k];
                                    stu2[k] = temp;
                                    sumCj[i] += (stu2[k].StudengCj-stu1[i].StudengCj);
                                    avgCj[i] = sumCj[i] / stu1.Count;
                                }
                            }
                            while ((avgCj[i] - avg) <- 0.5)
                            {
                                if (stu1[j].StudengCj < stu2[k].StudengCj)
                                {
                                    temp = stu1[j];
                                    stu1[j] = stu2[k];
                                    stu2[k] = temp;
                                    sumCj[i] += (stu2[k].StudengCj - stu1[i].StudengCj);
                                    avgCj[i] = sumCj[i] / stu1.Count;
                                }
                            }
                        }
                    }
                }
            }