快速排序

public class QuickSort
    {
        ///<summary>
        /// 分割函数
        ///</summary>
        ///<param name="list">待排序的数组</param>
        ///<param name="left">数组的左下标</param>
        ///<param name="right"></param>
        ///<returns></returns>
        public static int Division(List<int> list, int left, int right)
        {
            //首先挑选一个基准元素
            int baseNum = list[left];

            while (left < right)
            {
                while (left < right && list[right] >= baseNum)
                {
                    right = right - 1;
                }

                list[left] = list[right];

                while (left < right && list[left] <= baseNum)
                {
                    left = left + 1;
                }

                list[right] = list[left];
            }
            //最后就是把baseNum放到该left的位置
            list[left] = baseNum;

            //最终，我们发现left位置的左侧数值部分比left小，left位置右侧数值比left大
            //至此，我们完成了第一篇排序

            return left;
        }

        public static void QuickSortCore(List<int> list, int left, int right)
        {
            if (left < right)
            {
                int i = Division(list, left, right);
                QuickSortCore(list, left, i - 1);
                QuickSortCore(list, i + 1, right);
            }
        }

        private static int SortUnit(int[] array, int low, int high)
        {
            int key = array[low];
            while (low < high)
            {
                /*从后向前搜索比key小的值*/
                while (array[high] >= key && high > low)
                    --high;
                /*比key小的放左边*/
                array[low] = array[high];
                /*从前向后搜索比key大的值，比key大的放右边*/
                while (array[low] <= key && high > low)
                    ++low;
                /*比key大的放右边*/
                array[high] = array[low];
            }

            /*左边都比key小，右边都比key大。//将key放在游标当前位置。//此时low等于high */
            array[low] = key;
            //foreach (int i in array)
            //{
            //    Console.Write("{0}\t", i);
            //}
            return high;
        }

        public static void Sort(int[] array, int low, int high)
        {
            if (low >= high)
                return;
            /*完成一次单元排序*/
            int index = SortUnit(array, low, high);
            /*对左边单元进行排序*/
            Sort(array, low, index - 1);
            /*对右边单元进行排序*/
            Sort(array, index + 1, high);
        }
    }