希尔排序

public class ShellSort 
{
  public static void main(String args[])
  {
    int a[] = {10,5,10,2};
    System.out.println("this is shellsort:");
    ShellSort(a);
    output(a);
  }
  public static void output(int a[])//输出
  {
    int i;
    for(i = 0; i < a.length; i++)
    {
      System.out.print(a[i] + " ");
    }
    System.out.println();
  }
  public static void ShellSort(int a[])//希尔排序
  {
    int i,j,gap;
    for(gap = a.length / 2; gap >= 1; gap = gap / 2)//步长
    {
      for(i = gap; i < a.length; i++)
      {
        int temp = a[i];//保存a[i]的值
        j = i - gap;//从i = 0开始
        while(j >= 0 && temp < a[j])//直接插入排序
        {
          a[j + gap] = a[j];
          j -= gap;
        }
        a[j + gap] = temp;
      }
    }
  }
}