C# 排序

将前面写的几个排序算法整理了一个，合在一起。

1.适合于实现了IComparable接口的任何类型的数组

2.这个类可以当成一个工具类

3.以后如果实现了其他的排序算法还会再加进来，目前有直接插入排序，希尔排序，冒泡排序，快速排序，选择排序。其中冒泡和选择比较简单，

  希尔和快速排序比较复杂，都用上递归了。

    /// <summary>
    /// Dec:Sort Helper
    /// Author:david
    /// Create Date:2010-05-06
    /// </summary>
    public class SortHelper
    {
        /// <summary>
        /// Insert Sort
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="array"></param>
        public static void InsertSort<T>(T[] array) where T : IComparable
        {
            int length = array.Length;
            for (int i = 1; i < length; i++)
            {
                T temp = array[i];
                if (temp.CompareTo(array[i - 1])<0)
                {
                    for (int j = 0; j < i; j++)
                    {
                        if (temp.CompareTo(array[j])<0)
                        {
                            temp = array[j];
                            array[j] = array[i];
                            array[i] = temp;
                        }
                    }
                }
            }
        }
        /// <summary>
        /// Shell Sort
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="array"></param>
        public static void ShellSort<T>(T[] array) where T : IComparable
        {
            int length = array.Length;
            for (int h = length / 2; h > 0; h = h / 2)
            {
                for (int i = h; i < length; i++)
                {
                    T temp = array[i];
                    if (temp.CompareTo(array[i -h]) < 0)
                    {
                        for (int j = 0; j < i; j += h)
                        {
                            if (temp.CompareTo(array[j]) < 0)
                            {
                                temp = array[j];
                                array[j] = array[i];
                                array[i] = temp;
                            }
                        }
                    }
                }
            }
        }
        /// <summary>
        /// Bubble Sort
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="array"></param>
        public static void BubbleSort<T>(T[] array) where T : IComparable
        {
            int length = array.Length;
            for (int i = 0; i < length; i++)
            {
                T temp = array[i];
                for (int j = i; j < length; j++)
                {
                    if (temp.CompareTo(array[j]) >0)
                    {
                        temp = array[j];
                        array[j] = array[i];
                        array[i] = temp;
                    }
                }
            }
        }
        /// <summary>
        /// Quick Sort
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="array"></param>
        public static void QuickSort<T>(T[] array,int left,int right) where T : IComparable
        {
            
            if (left < right)
            {
               
                int middle = GetMiddleFroQuickSort<T>(array, left, right);
 
                QuickSort<T>(array, left, middle - 1);
                QuickSort<T>(array, middle + 1, right);
            }
           
        }
        /// <summary>
        /// get the index of the middle value for qucik sort
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="array"></param>
        /// <param name="left"></param>
        /// <param name="right"></param>
        /// <returns></returns>
        private static int GetMiddleFroQuickSort<T>(T[] array, int left, int right) where T : IComparable
        {
            T key = array[left];
            while (left < right)
            {
                while (left < right && key.CompareTo(array[right]) < 0)
                {
                    right--;
                }
                if (left < right)
                {
                    T temp = array[left];
                    array[left] = array[right];
                    //Console.WriteLine("array[{0}]:{1} ---->  arry[{2}]:{3}", left, temp, right, array[right]);
                    left++;
                }
                while (left < right && key.CompareTo(array[left]) > 0)
                {
                    left++;
                }
                if (left < right)
                {
                    T temp = array[right];
                    array[right] = array[left];
                    //Console.WriteLine("array[{0}]:{1} ----> arry[{2}]:{3}", right, temp, left, array[left]);
                    right--;
                }
                array[left] = key;
            }
            //Console.WriteLine("find the middle value {0} and the index {1}", array[left], left);
            return left;
        }
        /// <summary>
        /// selection sort
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="array"></param>
        /// <param name="left"></param>
        /// <param name="right"></param>
        public static void SelectionSort<T>(T[] array) where T : IComparable
        {
            int length = array.Length;
            for (int i = 0; i < length; i++)
            {
                T min = array[i];
                int minIndex = i ;
                for (int j = i+1; j < length; j++)
                {
                    if (min.CompareTo(array[j])>0)
                    {
                        min = array[j];
                        minIndex = j;
                    }
                }
                if (minIndex != i)
                {
                    array[minIndex] = array[i];
                    array[i] = min;
                    //Console.WriteLine("the min value is : {2} swap  {0} with {1}", array[minIndex], array[i],min);
                }
                //for (int k = 0; k <=i; k++)
                //{
                //    Console.Write(array[k] + "->");
                //}
                //Console.WriteLine();
                //Console.WriteLine();
            }
        }
    }