algorithm - Shell sort Java example

Question

Can anyone give me example about shell sort? I'm a new person in here who must learn about shell sort, but first I must find a Java shell sort example. I found one example in Google but it's too difficult.

Answer 1

Here, this code is very simple :

/**
   * Shellsort, using Shell’s (poor) increments.
   * @param a an array of Comparable items.
   */
  public static <T extends Comparable<? super T>>
  void shellsort( T [ ] a )
  {
    int j;
    for( int gap = a.length / 2; gap > 0; gap /= 2 )
    {
      for( int i = gap; i < a.length; i++ )
      {
         T tmp = a[ i ];
         for( j = i; j >= gap && tmp.compareTo( a[ j - gap ] ) < 0; j -= gap )
         {
           a[ j ] = a[ j - gap ];
         }
         a[ j ] = tmp;
      }
    }
  }

I stole it from a book called Data Structures and Algorithm Analysis in Java. It is very good book easy to understand. I advise you to read it.