前段时间要对字符串集合进行按长度排序，字符串长度长的排在队列前面，最短的排在最后，可以使用两种排序方法进行排序，其中快速排序的效能会好些，但快速排序在字符串的集合非常大的时候，有时会得不到正确的结果，具体原因还不清楚。
1.合拼排序的代码
using System;
using System.Collections.Generic;
using System.Text;namespace FtpproxyDownRule.DBUtility
{public class sortbyStringLength
{
/// <summary>
/// 使用合并排序
/// </summary>
/// <param name="orderstrings">待排序的集合</param>
public static void Mergesort(string[] orderstrings)
{
long arraylength = orderstrings.LongLength;
if (arraylength > 1)
{
//把集合分成两半,分别进行排序
long length = long.Parse(Convert.ToString(Math.Ceiling(orderstrings.LongLength / 2D)));string[] firstArray = new string[length];
string[] secondArray = new string[arraylength - length];
//把orderstrings前半部分复制到firstArray中
copyArray(orderstrings, firstArray, true);
//把orderstrings后半部分复制到secondArray中
copyArray(orderstrings, secondArray, false);
//递归调用,对firstArray分成两部分
Mergesort(firstArray);
Mergesort(secondArray);
//合并排序后的结果
merge(firstArray, secondArray, orderstrings);
}
}
/// <summary>
/// 对两个集合进行排序
/// </summary>
/// <param name="firstArray">待排序的集合</param>
/// <param name="secondArray">待排序的集合</param>
/// <param name="OriginalArray">firstArray,secondArray进行排序后得到的集合</param>
private static void merge(string[] firstArray, string[] secondArray, string[] OriginalArray)
{
long firstArraylength = firstArray.LongLength;
long secondArraylength = secondArray.LongLength;long i = 0, j = 0, k = 0;
while (i < firstArraylength && j < secondArraylength)
{
if (firstArray[i].Length > secondArray[j].Length)
{
OriginalArray[k] = firstArray[i];
i++;
}
else
{
OriginalArray[k] = secondArray[j];
j++;
}
k++;
}
if (i == firstArraylength)
{
copyArray(secondArray, OriginalArray, j, k);
}
else
{
copyArray(firstArray, OriginalArray, i, k);
}}
private static void copyArray(string[] OriginalArray, string[] firstArray, bool flag)
{
long OriginalLength = OriginalArray.LongLength;
long count = long.Parse(Convert.ToString(Math.Ceiling(OriginalLength / 2D)));
if (flag)
{
for (int i = 0; i < count; i++)
{firstArray[i] = OriginalArray[i];
}
}
else
{
long j = 0;
for (long i = count; i < OriginalLength; i++)
{
firstArray[j] = OriginalArray[i];
j++;
}
}}
private static void copyArray(string[] OriginalArray, string[] firstArray, long OriginalArraybenginIndex, long FirstArraybenginIndex)
{long OriginalArrayLenth = OriginalArray.LongLength;
for (long i = OriginalArraybenginIndex; i < OriginalArrayLenth; i++)
{
firstArray[FirstArraybenginIndex] = OriginalArray[i];
FirstArraybenginIndex++;
}}
}}
快速排序的代码：
class quickSortbyStringLenth
{
public static void QuickSort(string[] orderstring)
{
Qsort(orderstring, 0, orderstring.LongLength - 1);
}
private static void Qsort(string[] orderstrings, long lowindex, long highindex)
{
if (lowindex < highindex)
{
long pivotloc = Partition(orderstrings, lowindex, highindex);
Qsort(orderstrings, lowindex, pivotloc - 1);
Qsort(orderstrings, pivotloc + 1, highindex);
}
}
private static long Partition(string[] OriginalArray, long lowIndex, long highIndex)
{
//OriginalArray[0] = OriginalArray[lowIndex];
string p = OriginalArray[lowIndex];
while (lowIndex < highIndex)
{
while (lowIndex < highIndex && OriginalArray[highIndex].Length <= p.Length) --highIndex;
OriginalArray[lowIndex] = OriginalArray[highIndex];
while (lowIndex < highIndex && OriginalArray[lowIndex].Length >= p.Length) ++lowIndex;
OriginalArray[highIndex] = OriginalArray[lowIndex];
}
OriginalArray[lowIndex] = p;
return lowIndex;
}
}