@Test
  public void testSort() {
    String[] sortable = {"S", "O", "R", "T", "E", "X", "A", "M", "P", "L", "E"};
    String[] sorted = {"A", "E", "E", "L", "M", "O", "P", "R", "S", "T", "X"};
    Insertion.sort(sortable);

    assertEquals(sorted, sortable);
  }
Exemple #2
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  private static void sort(Comparable[] a, int lo, int hi) {
    int N = hi - lo + 1;
    if (N <= CUT_OFF) {
      Insertion.sort(a, lo, hi);
      return;
    } else if (N <= 40) {
      int m = median3(a, lo, lo + N / 2, hi);
      exch(a, m, lo);
    }

    // use Tukey ninther as partitioning element
    else {
      int eps = N / 8;
      int mid = lo + N / 2;
      int m1 = median3(a, lo, lo + eps, lo + eps + eps);
      int m2 = median3(a, mid - eps, mid, mid + eps);
      int m3 = median3(a, hi - eps - eps, hi - eps, hi);
      int ninther = median3(a, m1, m2, m3);
      exch(a, ninther, lo);
    }

    // Bentley-McIlroy 3-way partitioning
    int i = lo, j = hi + 1;
    int p = lo, q = hi + 1;
    Comparable v = a[lo];
    while (true) {
      while (less(a[++i], v)) if (i == hi) break;
      while (less(v, a[--j])) if (j == lo) break;
      if (i >= j) break;
      exch(a, i, j);
      if (eq(a[i], v)) exch(a, ++p, i);
      if (eq(a[j], v)) exch(a, --q, j);
    }
    exch(a, lo, j);

    i = j + 1;
    j = j - 1;
    for (int k = lo + 1; k <= p; k++) exch(a, k, j--);
    for (int k = hi; k >= q; k--) exch(a, k, i++);

    sort(a, lo, j);
    sort(a, i, hi);
  }