学步园

堆排序的主要原理就是利用堆的特点，首先生成最大堆，然后每次取堆的root和最后一个叶子交换，剔除最后叶子。然后再次生成最大堆，循环。

  /// <summary>
        /// 堆排序
        /// </summary>
        /// <param name="Myarray"></param>
        /// <returns></returns>
        private int[] HeapSotr(int[] Myarray)
        {
            int i;
            HeadAdjust(Myarray, 0, Myarray.Length-1);
            for (i = Myarray.Length-1; i > 0; i--)
            {
                Swap(Myarray, 0, i);
                HeadAdjust(Myarray, 0, i-1);
            }

            return Myarray;
        }
        /// <summary>
        /// 生成堆
        /// </summary>
        /// <param name="Myarray"></param>
        /// <param name="s"></param>
        /// <param name="m"></param>
        private void HeadAdjust(int[] Myarray, int low, int high)
        {
          if ((low < high) && (high <Myarray .Length))
            {
                int j = 0;
                int temp = 0;
                int k = 0;
              for(int i=high/2;i>=low;i--)
              {
                  k = i;
                  j = 2 * k+1 ;
                  temp = Myarray[i];
                  while (j+1 <=high)
                  {
                      if  (Myarray[j] < Myarray[j + 1])
                          ++j;
                      if (temp < Myarray[j])
                      {
                          Myarray[k] = Myarray[j];
                          k = j;
                          j = 2 * k+1 ;
                      }
                      else
                      {
                          j = high + 1;
                      }
                      Myarray[k] = temp;
                  }
              }
            }
       
        }

 /// <summary>
        /// 交换值
        /// </summary>
        /// <param name="Myarray"></param>
        /// <param name="i"></param>
        /// <param name="j"></param>
        private void Swap(int[] Myarray, int i, int j)
        {
            int temp = Myarray[i];
            Myarray[i] = Myarray[j];
            Myarray[j] = temp;
        }