c# 文件快速排序(按文件创建时间)的代码

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
/// <summary>
/// 快速排序算法
/// </summary>
public class MyQuickSort
{
public MyQuickSort()
{
//
// TODO: Add constructor logic here
//
}

/// <summary>
/// 快速排序算法
/// </summary>
/// 快速排序为不稳定排序,时间复杂度O(nlog2n),为同数量级中最快的排序方法
/// <param name="arr">划分的数组</param>
/// <param name="low">数组低端上标</param>
/// <param name="high">数组高端下标</param>
/// <returns></returns>
static int Partition(FileInfo[] arr, int low, int high)
{
//进行一趟快速排序,返回中心轴记录位置
// arr[0] = arr[low];
FileInfo pivot = arr[low];//把中心轴置于arr[0]
while (low < high)
{
while (low < high && arr[high].CreationTime <= pivot.CreationTime)
--high;
//将比中心轴记录小的移到低端
Swap(ref arr[high], ref arr[low]);
while (low < high && arr[low].CreationTime >= pivot.CreationTime)
++low;
Swap(ref arr[high], ref arr[low]);
//将比中心轴记录大的移到高端
}
arr[low] = pivot; //中心轴移到正确位置
return low; //返回中心轴位置
}
static void Swap(ref FileInfo i, ref FileInfo j)
{
FileInfo t;
t = i;
i = j;
j = t;
}
/// <summary>
/// 快速排序算法
/// </summary>
/// 快速排序为不稳定排序,时间复杂度O(nlog2n),为同数量级中最快的排序方法
/// <param name="arr">划分的数组</param>
/// <param name="low">数组低端上标</param>
/// <param name="high">数组高端下标</param>
public static void QuickSort(FileInfo[] arr, int low, int high)
{
if (low <= high - 1)//当 arr[low,high]为空或只一个记录无需排序
{
int pivot = Partition(arr, low, high);
QuickSort(arr, low, pivot - 1);
QuickSort(arr, pivot + 1, high);
}
}

}

System.IO.DirectoryInfo dir = new DirectoryInfo(currentFolder);
System.IO.FileInfo[] files = dir.GetFiles();
MyQuickSort.QuickSort(files, 0, files.Length - 1);//按时间排序