C# 常用算法

/// <summary>
    ///  1+2+3+....+n的递归算法
    /// </summary>
    /// <param name="i"></param>
    /// <returns></returns>
    public static int Process1(int i)
    {
        //计算1+2+3+4+...+100的值

        if (i == 0) return 1;
        if (i == 1) return 1;
        return Process1(i - 2) + Process1(i - 1);
    }
    /// <summary>
    /// 1+2+3+....+n的非递归算法
    /// </summary>
    /// <param name="i"></param>
    /// <returns></returns>
    public static int Process2(int i)
    {
        //计算1+2+3+4+...+100的值

        if (i == 0) return 0;
        return Process2(i - 1) + i;
    }

    /// <summary>
    /// 1-2+3-4+5-....+n的非递归算法
    /// </summary>
    /// <param name="isum"></param>
    /// <param name="itype"></param>
    /// <returns></returns>
    public static int Process0(int isum, int itype)
    {
        int sum = 0;

        for (int i = 1; i <= isum; i++)
        {
            if (itype == 1)
            {
                if (i % 2 != 0)
                {
                    sum += i;
                }
                else
                {
                    sum += (-1) * i;
                }
            }
            else
            {
                sum += i;
            }
        }
        return sum;
    }
    /// <summary>
    /// 冒泡法排序
    /// </summary>
    /// <param name="arrLen"></param>
    public static void order1(ref int[] arrLen)
    {
        int temp;
        for (int i = 0; i < arrLen.Length; i++)//冒泡法排序
            for (int j = i + 1; j < arrLen.Length; j++)
                if (arrLen[i] > arrLen[j])
                {
                    temp = arrLen[i];
                    arrLen[i] = arrLen[j];
                    arrLen[j] = temp;
                }
    }

    /// <summary>
    /// 冒泡法排序
    /// </summary>
    /// <param name="arrLen"></param>
    public static void order2(ref int[] arrLen)
    {
        for (int i = 0; i < arrLen.Length - 1; i++)
        {
            for (int j = 0; j < arrLen.Length - 1 - i; j++)
            {
                if (arrLen[j] > arrLen[j + 1])
                {
                    int temp = arrLen[j];
                    arrLen[j] = arrLen[j + 1];
                    arrLen[j + 1] = temp;
                }
            }
        }
    }

    
    //折半查找、二分算法
    //数组必须按照一定的顺序
    //参数：最大，最小，目标（参数类型为整数）
    public static int BinarySearch(int min, int max, int num)
    {
        if (min == max) return -1;
        int mid = (min + max) / 2;
        if (a[mid] == num) return mid;
        else if (a[mid] < num)
        {
            return BinarySearch(mid + 1, max, num);
        }
        else
        {
            return BinarySearch(min, mid - 1, num);
        }
    }
    //折半查找、二分算法
    //非递归算法
    public static int BinarySearch_F(int num)
    {
        int min = 0;
        int max = 9;
        int mid;
        while (min <= max)
        {
            mid = (min + max) / 2;
            if (a[mid] == num) return mid;
            else if (a[mid] > num) max = mid - 1;
            else min = mid + 1;
        }
        return -1;
    }
 int a[10] ={1,5,10,13,17,23,65,77,81,93}