Shell排序(插入排序的加强版) C#解法

using System;

namespace 插入排序
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] arr = new int[] { 9, 1, 2, 5, 7, 4, 8, 6, 3, 5 };
            ShellSort(arr);
            Console.ReadKey();
        }
        public static void ShellSort(int[] array)
        {
            int gap = array.Length / 2;

            while (1 <= gap)
            {
                for (int i = gap; i < array.Length; i++)
                {
                    int j = 0;
                    int temp = array[i];
                    for (j = i - gap; j >= 0 && temp < array[j]; j = j - gap)
                    {
                        array[j + gap] = array[j];
                    }
                    array[j + gap] = temp;
                }
                Console.WriteLine("gap={0}", gap);
                foreach (int n in array)
                {
                    Console.Write("{0} ", n);
                }
                Console.WriteLine();
                gap = gap / 2;
            }
        }
    }
}

思路:把数组按gap步长分组,之后将每组数据从小到大排序,遍历一次之后将gap/2,继续排序,直到gap=1,排序结束.时间复杂度为:O(n^(1.3—2)),因此Shell排序较插入排序有着更好的性能.