CODE EXAMPLE FOR JAVA

quicksort java

//GOD's quicksort
public static <E extends Comparable<E>> List<E> sort(List<E> col) {
  if (col == null || col.isEmpty())
    return Collections.emptyList();
  else {
    E pivot = col.get(0);
    Map<Integer, List<E>> grouped = col.stream()
      .collect(Collectors.groupingBy(pivot::compareTo));
    return Stream.of(sort(grouped.get(1)), grouped.get(0), sort(grouped.get(-1)))
      .flatMap(Collection::stream).collect(Collectors.toList());
  }
}