C# 一些算法

1.输出下列的格式的数字

/*
                       1,5
                    1,4   2,5
                  1,3  2,4  3,5
               1,2  2,3  3,4  4,5   
             
             */

    

int[] a = { 1, 2, 3, 4, 5 };
            for (int i = 0; i < a.Length - 1; i++)
            {
                for (int j = 0; j < i + 1; j++)
                {
                    Console.WriteLine("(" + a[j] + "," + a[a.Length - 1 - i + j] + ")");
                }
            }

2./*一列数的规则如下: 1、1、2、3、5、8、13、21、34...... 求第30位数是多少， 用递归算法实现。*/

public static int DealNum(int i)
        {
            if (i <= 0)
                return 0;
            else if (i > 0 && i <= 2)
                return 1;
            else return DealNum(i - 1) + DealNum(i - 2);
        }
  调用： Console.write(DealNum(30));

3.//冒泡排序

public static int[] MaoPao(int[] Data)
        {
            int temp = 0;
            int length = Data.Length - 1;
            for (int i = 0; i < length; i++)
            {
                for (int j = length; j > i; j--)
                {
                    if (Data[j] > Data[j - 1])
                    {
                        temp = Data[j];
                        Data[j] = Data[j - 1];
                        Data[j - 1] = temp;
                    }
                }
            }
            return Data;

        }
 调用：int[] array = new int[] { 1, 4, 2, 3, 5 };
        int[] newdata = MaoPao(array);
            for (int i = 0; i < newdata.Length; i++)
            {
                Console.Write(newdata[i]);
            }

4. /* 求一下表达式的值 1-2+3-4+......+m */

public static int DealNum(int m)
   {
    int sum =0;
    bool flag=true;
    for(int i=1;i<=m;i++)
    {
       if(flag)
        sum+=i;
           else
         sum-=i;
           flag=!flag;
    }
       return sum;
    }