ASP.NET技巧：用C#实现几种经典排序算法

3、快速排序

快速排序
class QuickSorter
{
private void swap(ref int l, ref int r)
{
int temp;
temp = l;
l = r;
r = temp;
}
public void Sort(int[] list, int low, int high)
{
int pivot;//存储分支点
int l, r;
int mid;
if (high <= low)
return;
else if (high == low + 1)
{
if (list[low] > list[high])
swap(ref list[low], ref list[high]);
return;
}
mid = (low + high) >> 1;
pivot = list[mid];
swap(ref list[low], ref list[mid]);
l = low + 1;
r = high;
do
{
while (l <= r && list[l] < pivot)
l++;
while (list[r] >= pivot)
r–;
if (l < r)
swap(ref list[l], ref list[r]);
} while (l < r);
list[low] = list[r];
list[r] = pivot;
if (low + 1 < r)
Sort(list, low, r – 1);
if (r + 1 < high)
Sort(list, r + 1, high);
}
}

4、插入排序

插入排序
public class InsertionSorter
{
public void Sort(int[] arr)
{
for (int i = 1; i < arr.Length; i++)
{
int t = arr[i];
int j = i;
while ((j > 0) && (arr[j - 1] > t))
{
arr[j] = arr[j - 1];//交换顺序
–j;
}
arr[j] = t;
}
}
}

5、希尔排序

希尔排序
public class ShellSorter
{
public void Sort(int[] arr)
{
int inc;
for (inc = 1; inc <= arr.Length / 9; inc = 3 * inc + 1) ;
for (; inc > 0; inc /= 3)
{
for (int i = inc + 1; i <= arr.Length; i += inc)
{
int t = arr[i - 1];
int j = i;
while ((j > inc) && (arr[j - inc - 1] > t))
{
arr[j - 1] = arr[j - inc - 1];//交换数据
j -= inc;
}
arr[j - 1] = t;
}
}
}
}

6、归并排序

归并排序
/// <summary>
/// 归并排序之归：归并排序入口
/// </summary>
/// <param name=”data”>无序的数组</param>
/// <returns>有序数组</returns>
/// <author>Lihua(www.zivsoft.com)</author>
int[] Sort(int[] data)
{
//取数组中间下标
int middle = data.Length / 2;
//初始化临时数组let,right，并定义result作为最终有序数组
int[] left = new int[middle], right = new int[middle], result = new int[data.Length];
if (data.Length % 2 != 0)//若数组元素奇数个，重新初始化右临时数组
{
right = new int[middle + 1];
}
if (data.Length <= 1)//只剩下1 or 0个元数，返回，不排序
{
return data;
}
int i = 0, j = 0;
foreach (int x in data)//开始排序
{
if (i < middle)//填充左数组
{
left[i] = x;
i++;
}
else//填充右数组
{
right[j] = x;
j++;
}
}
left = Sort(left);//递归左数组
right = Sort(right);//递归右数组
result = Merge(left, right);//开始排序
//this.Write(result);//输出排序,测试用(lihua debug)
return result;
}
/// <summary>
/// 归并排序之并:排序在这一步
/// </summary>
/// <param name=”a”>左数组</param>
/// <param name=”b”>右数组</param>
/// <returns>合并左右数组排序后返回</returns>
int[] Merge(int[] a, int[] b)
{
//定义结果数组，用来存储最终结果
int[] result = new int[a.Length + b.Length];
int i = 0, j = 0, k = 0;
while (i < a.Length && j < b.Length)
{
if (a[i] < b[j])//左数组中元素小于右数组中元素
{
result[k++] = a[i++];//将小的那个放到结果数组
}
else//左数组中元素大于右数组中元素
{
result[k++] = b[j++];//将小的那个放到结果数组
}
}
while (i < a.Length)//这里其实是还有左元素，但没有右元素
{
result[k++] = a[i++];
}
while (j < b.Length)//右右元素，无左元素
{
result[k++] = b[j++];
}
return result;//返回结果数组
}

7、基数排序

基数排序
//基数排序
public int[] RadixSort(int[] ArrayToSort, int digit)
{
//low to high digit
for (int k = 1; k <= digit; k++)
{
//temp array to store the sort result inside digit
int[] tmpArray = new int[ArrayToSort.Length];
//temp array for countingsort
int[] tmpCountingSortArray = new int[10]{0,0,0,0,0,0,0,0,0,0};
//CountingSort
for (int i = 0; i < ArrayToSort.Length; i++)
{
//split the specified digit from the element
int tmpSplitDigit = ArrayToSort[i]/(int)Math.Pow(10,k-1) – (ArrayToSort[i]/(int)Math.Pow(10,k))*10;
tmpCountingSortArray[tmpSplitDigit] += 1;
}
for (int m = 1; m < 10; m++)
{
tmpCountingSortArray[m] += tmpCountingSortArray[m - 1];
}
//output the value to result
for (int n = ArrayToSort.Length – 1; n >= 0; n–)
{
int tmpSplitDigit = ArrayToSort[n] / (int)Math.Pow(10,k – 1) – (ArrayToSort[n]/(int)Math.Pow(10,k)) * 10;
tmpArray[tmpCountingSortArray[tmpSplitDigit]-1] = ArrayToSort[n];
tmpCountingSortArray[tmpSplitDigit] -= 1;
}
//copy the digit-inside sort result to source array
for (int p = 0; p < ArrayToSort.Length; p++)
{
ArrayToSort[p] = tmpArray[p];
}
}
return ArrayToSort;
}

8、计数排序

计数排序
//计数排序
/// <summary>
/// counting sort
/// </summary>
/// <param name=”arrayA”>input array</param>
/// <param name=”arrange”>the value arrange in input array</param>
/// <returns></returns>
public int[] CountingSort(int[] arrayA, int arrange)
{
//array to store the sorted result,
//size is the same with input array.
int[] arrayResult = new int[arrayA.Length];
//array to store the direct value in sorting process
//include index 0;
//size is arrange+1;
int[] arrayTemp = new int[arrange+1];
//clear up the temp array
for(int i = 0; i <= arrange; i++)
{
arrayTemp[i] = 0;
}
//now temp array stores the count of value equal
for(int j = 0; j < arrayA.Length; j++)
{
arrayTemp[arrayA[j]] += 1;
}
//now temp array stores the count of value lower and equal
for(int k = 1; k <= arrange; k++)
{
arrayTemp[k] += arrayTemp[k - 1];
}
//output the value to result
for (int m = arrayA.Length-1; m >= 0; m–)
{
arrayResult[arrayTemp[arrayA[m]] – 1] = arrayA[m];
arrayTemp[arrayA[m]] -= 1;
}
return arrayResult;
}

9、小根堆排序

小根堆排序
/// <summary>
/// 小根堆排序
/// </summary>
/// <param name=”dblArray”></param>
/// <param name=”StartIndex”></param>
/// <returns></returns>

private void HeapSort(ref double[] dblArray)
{
for (int i = dblArray.Length – 1; i >= 0; i–)
{
if (2 * i + 1 < dblArray.Length)
{
int MinChildrenIndex = 2 * i + 1;
//比较左子树和右子树，记录最小值的Index
if (2 * i + 2 < dblArray.Length)
{
if (dblArray[2 * i + 1] > dblArray[2 * i + 2])
MinChildrenIndex = 2 * i + 2;
}
if (dblArray[i] > dblArray[MinChildrenIndex])
{

ExchageValue(ref dblArray[i], ref dblArray[MinChildrenIndex]);
NodeSort(ref dblArray, MinChildrenIndex);
}
}
}
}

/// <summary>
/// 节点排序
/// </summary>
/// <param name=”dblArray”></param>
/// <param name=”StartIndex”></param>

private void NodeSort(ref double[] dblArray, int StartIndex)
{
while (2 * StartIndex + 1 < dblArray.Length)
{
int MinChildrenIndex = 2 * StartIndex + 1;
if (2 * StartIndex + 2 < dblArray.Length)
{
if (dblArray[2 * StartIndex + 1] > dblArray[2 * StartIndex + 2])
{
MinChildrenIndex = 2 * StartIndex + 2;
}
}
if (dblArray[StartIndex] > dblArray[MinChildrenIndex])
{
ExchageValue(ref dblArray[StartIndex], ref dblArray[MinChildrenIndex]);
StartIndex = MinChildrenIndex;
}
}
}

/// <summary>
/// 交换值
/// </summary>
/// <param name=”A”></param>
/// <param name=”B”></param>
private void ExchageValue(ref double A, ref double B)
{
double Temp = A;
A = B;
B = Temp;
}