Implements a Shellsort - Java Data Structure

Java examples for Data Structure:Sort

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Description

Implements a Shellsort

Demo Code




class Shell {//from   w  w  w.j  av  a2s.c om

  public static void sort(Comparable[] a) {
    int N = a.length;
    int h = 1; // boundary subarray

    while (h < N / 3)
      h = 3 * h + 1; // 1, 4, 13, 40 ...

    while (h >= 1) {
      for (int i = h; i < N; i++) {
        // insertion sort
        for (int j = i; j >= h && less(a[j], a[j - h]); j -= h)
          exch(a, j, j - h);
      }

      h = h / 3;
    }
  }

  private static boolean less(Comparable v, Comparable w) {
    return v.compareTo(w) < 0;
  }

  private static void exch(Comparable[] a, int i, int j) {
    Comparable swap = a[i];
    a[i] = a[j];
    a[j] = swap;
  }

  public static void main(String[] args) {
    Integer[] data = new Integer[] { 95, 29, 57, 82, 41, 83, 52, 21, 94, 79 };
    sort(data);

    System.out.print("Array sorted by Shellsort: ");
    for (Integer x : data) {
      System.out.printf("%s ", x);
    }
  }
}

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