测试代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace HeapSort{    class Program    {        static void Main(string[] args)        {            var arr = new int[] { 10, 7, 5 ,1,2,5};            List
    
      src = new List
     
      (arr);            HeapSort
      
        heapSort = new HeapSort
       
        ((a, b) => { return a - b; }, src);                        heapSort.TryAddNumber(6);            heapSort.TryAddNumber(7);            heapSort.TryAddNumber(8);            heapSort.TryAddNumber(9);            heapSort.TryAddNumber(10);            Console.WriteLine(string.Join(",", heapSort.MinHeapsortToDescend().ConvertAll((t) => t.ToString()).ToArray()));            Console.ReadLine();        }    }}
       
      
     
    

算法实现：

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace HeapSort{    /// 
    /// 使用最小堆算法计算 TopN，参考 http://blog.csdn.net/morewindows/article/details/6709644    /// 最小堆性质:"父结点的键值总是小于或等于任何一个子节点的键值"    /// 
    /// 
        class HeapSort
    
         {        Comparison
     
       comparison;        List
      
        minHeapList;        public HeapSort(Comparison
       
         _comparison, List
        
          list)        {            comparison = _comparison;            MakeMinHeap(list);        }        /* 这里只是将最小堆用于计算TopN，因此不需要添加节点        //  新加入i结点  其父结点为(i - 1) / 2          void MinHeapFixup(int i)        {            int parent;            var temp = minHeapList[i];            parent = (i - 1) / 2;      //父结点              while (parent >= 0 && i != 0)            {                //if (list[parent] <= temp)                if (comparison(minHeapList[parent], temp) <= 0)                    break;                minHeapList[i] = minHeapList[parent];     //把较大的子结点往下移动,替换它的子结点                  i = parent;                parent = (i - 1) / 2;            }            minHeapList[i] = temp;        }        //在最小堆中加入新的数据nNum          void MinHeapAddNumber(int n, T nNum)        {            minHeapList[n] = nNum;            MinHeapFixup(n);        }*/        //  从i节点开始调整,n为节点总数 从0开始计算 i节点的子节点为 2*i+1, 2*i+2          void MinHeapFixdown(int i, int n)        {            int leftChild;            var temp = minHeapList[i];            leftChild = 2 * i + 1;            while (leftChild < n)            {                //if (leftChild + 1 < n && a[leftChild + 1] < a[leftChild]) //在左右孩子中找最小的                  if (leftChild + 1 < n && comparison(minHeapList[leftChild + 1], minHeapList[leftChild]) < 0) //在左右孩子中找最小的                      leftChild++;                //if (a[leftChild] >= temp)                if (comparison(minHeapList[leftChild], temp) >= 0)                    break;                minHeapList[i] = minHeapList[leftChild];     //把较小的子结点往上移动,替换它的父结点                  i = leftChild;                leftChild = 2 * i + 1;            }            minHeapList[i] = temp;        }        /* 在TopN中不需要这样做        //在最小堆中删除数          void MinHeapDeleteNumber(int n)        {            Swap(0, n - 1);            MinHeapFixdown(0, n - 1);        }         */        /// 
         
 /// 尝试添加节点，如果小于等于最小根，不处理 /// 
        /// 
                 public void TryAddNumber(T item)        {            if (comparison(minHeapList[0], item) >= 0)//如果小于等于最小根，不处理            {                return;            }            minHeapList[0] = item;//直接覆盖根节点,然后向下比较,以确保最小堆性质:"父结点的键值总是小于或等于任何一个子节点的键值"            MinHeapFixdown(0, minHeapList.Count);        }        /// 
         
 /// 排序建立最小堆 /// 
        void MakeMinHeap(List
         
           list) { minHeapList = list; for (int i = list.Count / 2 - 1; i >= 0; i--) MinHeapFixdown(i, list.Count); } void Swap(int index1, int index2) { var temp = minHeapList[index1]; minHeapList[index1] = minHeapList[index2]; minHeapList[index2] = temp; } /// 
          
 /// 排序,在插入未完成之前，千万不要调用排序，这会破坏最小堆的性质 /// 
 public List
          
            MinHeapsortToDescend() { for (int i = minHeapList.Count - 1; i >= 1; i--) { Swap(i, 0); MinHeapFixdown(0, i); } return minHeapList; } }}