Method leastOf

output/java_guava/1.4.18/Ordering.java:684–701

Returns the k least elements of the given iterable according to this ordering, in order from least to greatest. If there are fewer than k elements present, all will be included. The implementation does not necessarily use a stable sorting algorithm; when multiple elements

(Iterable<E> iterable, int k)

  public <E extends T> List<E> leastOf(Iterable<E> iterable, int k) {
    if (iterable instanceof Collection) {
      Collection<E> collection = (Collection<E>) iterable;
      if (collection.size() <= 2L * k) {
        // In this case, just dumping the collection to an array and sorting is
        // faster than using the implementation for Iterator, which is
        // specialized for k much smaller than n.
        @SuppressWarnings("unchecked") // c only contains E's and doesn't escape
        E[] array = (E[]) collection.toArray();
        Arrays.sort(array, this);
        if (array.length > k) {
          array = ObjectArrays.arraysCopyOf(array, k);
        }
        return Collections.unmodifiableList(Arrays.asList(array));
      }
    }
    return leastOf(iterable.iterator(), k);
  }

  /**
   * Returns the {@code k} least elements from the given iterator according to