C#实现所有经典排序算法
1、选择排序

选择排序
class SelectionSorter   
{   
    private int min;   
    public void Sort(int[] arr)   
    {   
        for (int i = 0; i < arr.Length - 1; ++i)   
        {   
            min = i;   
            for (int j = i + 1; j < arr.Length; ++j)   
            {   
                if (arr[j] < arr[min])   
                    min = j;   
            }   
            int t = arr[min];   
            arr[min] = arr[i];   
            arr[i] = t;   
        }   
    }   
}

2、冒泡排序

冒泡排序
class EbullitionSorter   
{   
    public void Sort(int[] arr)   
    {   
        int i, j, temp;   
        bool done = false;   
        j = 1;   
        while ((j < arr.Length) && (!done))//判断长度   
        {   
            done = true;   
            for (i = 0; i < arr.Length - j; i++)   
            {   
                if (arr[i] > arr[i + 1])   
                {   
                    done = false;   
                    temp = arr[i];   
                    arr[i] = arr[i + 1];//交换数据   
                    arr[i + 1] = temp;   
                }   
            }   
            j++;   
        }   
    }     
}

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
        }
注：此算法由周利华提供（http://www.cnblogs.com/architect/archive/2009/05/06/1450489.html
）

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;
        }