堆排序算法

/**n个关键字序列Kl，K2，…，Kn称为(Heap)，当且仅当该序列满足如下性质(简称为堆性质)：
　*(1) ki≤K2i且ki≤K2i+1 或(2)Ki≥K2i且ki≥K2i+1(1≤i≤ n)
*/

using System;
using System.Collections.Generic;
using System.Text;

namespace heapSortAlgorithm
{
public class Node
{
public int data;
public Node(int key)
{
data = key;
}
}

class Heap
{
//const int maxSize = 10;
//int currSize;
//Node[] heapArray = new Node[maxSize];
public void ShiftUp(int index)
{
int parent = (index - 1) / 2;
Node bottom = heapArray[index];
while ((index > 0) && (heapArray[parent].data < bottom.data))
{
heapArray[index] = heapArray[parent];
index = parent;
parent = (parent - 1) / 2;
}
heapArray[index] = bottom;
}

public bool Insert(int key)
{
if (currSize == maxSize)
return false;
heapArray[currSize] = new Node(key);
ShiftUp(currSize);//This sentence is not existed in the original segment.
currSize++;
return true;
}

public Node Remove()
{
Node root = heapArray[0];
currSize--;
heapArray[0] = heapArray[currSize];
ShiftDown(0);
return root;
}

public void ShiftDown(int index)
{
int largerChild;
Node top = heapArray[index];
while (index < (int)(currSize / 2))
{
int leftChild = 2 * index + 1;
int rightChild = leftChild + 1;
if ((rightChild < currSize) && heapArray[leftChild].data < heapArray[rightChild].data)
largerChild = rightChild;
else
largerChild = leftChild;
if (top.data >= heapArray[largerChild].data)
break;
heapArray[index] = heapArray[largerChild];
index = largerChild;
}
heapArray[index] = top;
}

Node[] heapArray = null;
private int maxSize = 0;
private int currSize = 0;
public Heap(int maxSize)
{
this.maxSize = maxSize;
heapArray = new Node[maxSize];
}
public bool InsertAt(int pos, Node nd)
{
heapArray[pos] = nd;
return true;
}
public void ShowArray()
{
for (int i = 0; i < maxSize; i++)
{
if (heapArray[i] != null)
System.Console.Write(heapArray[i].data + " ");
}
}
static void Main()
{
const int SIZE = 9;
Heap aHeap = new Heap(SIZE);
Random RandomClass = new Random();
for (int i = 0; i < SIZE; i++)
{

int rn = RandomClass.Next(1, 100);
aHeap.Insert(rn);
}
Console.Write("Random: ");
aHeap.ShowArray();
Console.WriteLine();
Console.Write("Heap: ");
for (int i = (int)SIZE / 2 - 1; i >= 0; i--)
aHeap.ShiftDown(i);
aHeap.ShowArray();
for (int i = SIZE - 1; i >= 0; i--)
{
Node bigNode = aHeap.Remove();
aHeap.InsertAt(i, bigNode);
}
Console.WriteLine();
Console.Write("Sorted: ");
aHeap.ShowArray();

Console.ReadKey();
}
}

}