排序算法

 /// <summary>
        /// 二分查找
        /// </summary>
        /// <param name="arr"></param>
        /// <param name="num"></param>
        /// <returns></returns>
        public static int find(int[] arr, int num)
        {
            int l = 0, h = arr.Length - 1;
            while (l<=h)
            {
                int middle = (l + h) / 2;
                if (arr[middle] == num) return num;
                if (arr[middle] > num)
                {
                    
                    h = middle - 1;
                }
                else
                {
                    l = middle + 1;
                }
            }
            return -1;
        }

        /// <summary>
        /// 快速排序
        /// </summary>
        /// <param name="arr"></param>
        /// <param name="l"></param>
        /// <param name="r"></param>
        /// <returns></returns>
        public static int[] FastSort(int[] arr, int l, int r)
        {
            int i = l, j = r;

            int radom = arr[(l + r) / 2];

            while (i <= j)
            {
                while (arr[i] < radom)
                {
                    i++;
                }
                while (arr[j] > radom)
                {
                    j--;
                }

                if (i <= j)
                {
                    int temp;
                    temp = arr[i];
                    arr[i] = arr[j];
                    arr[j] = temp;

                    i++;
                    j--;
                }
            }

            if (l < j)
            {
                FastSort(arr, l, j);
            }

            if (r > i)
            {
                FastSort(arr, i, r);
            }

            return arr;
        }

        /// <summary>
        /// 冒泡排序
        /// </summary>
        /// <param name="arr"></param>
        /// <returns></returns>
        public static int[] BubblingSort(int[] arr)
        {
            for (int i = 0; i < arr.Length - 1; i++)
            {
                for (int j = 0; j < arr.Length - 1 - i; j++)
                {
                    if (arr[j] > arr[j + 1])
                    {
                        int temp;
                        temp = arr[j];
                        arr[j] = arr[j+1];
                        arr[j+1] = temp;
                    }
                   
                }
            }
            return arr;
        }