堆排序

 public void HeapSort(int[] data) {
            //创建大顶堆
            for (int i = 0; i < data.Length; ++i)
            {
                Add(data, i);
            }
            //开始排序
            for (int i = data.Length - 1; i >= 0; --i)
            {
                int mark = data[i];
                data[i] = data[0];
                data[0] = mark;
                CheckHeap(data,0,i-1);
            }
            Console.WriteLine(data);
        }
        public void Add(int[] heap,int idx) {
            int father = (idx - 1) / 2;
            if (father >= 0 && heap[idx] > heap[father]) {
                //如果父节点比本节点小，则交换
                int mark = heap[idx];
                heap[idx] = heap[father];
                heap[father] = mark;
                //交换之后继向上迭代
                Add(heap,father);
            }
        }
        public void CheckHeap(int[] heap,int idx,int len) {
            //限制边界，当把堆顶的元素放到最后时，堆的大小就变为了原堆大小 - 1
            int left = (2 * idx + 1 > len) ?idx: (2 * idx + 1);
            int right = (2 * idx + 2 > len) ? idx : (2 * idx + 2);
            bool _change = heap[idx] < Math.Max(heap[left],heap[right]);
            if (_change) {
                if (Math.Max(heap[left], heap[right]) == heap[left])
                {
                    //找出子节点中最大的一个，并交换
                    int mark = heap[idx];
                    heap[idx] = heap[left];
                    heap[left] = mark;
                    //交换后继续向下迭代，直到限制的边界，也就是此时堆的大小
                    CheckHeap(heap, left, len);
                }
                else {
                    int mark = heap[idx];
                    heap[idx] = heap[right];
                    heap[right] = mark;
                    CheckHeap(heap, right, len);
                }
            }
        }