Heapsort

template <class RAIter>
void g_heap_sort (RAIter beg, RAIter end)
{
  if (end - beg <= 1)
    return;
  size_t size = end - beg, k;

  // push elements onto heap one at a time
  for (k = 0; k < size; ++k)
    g_push_heap(beg, beg + (k + 1));
   
  // keep popping largest remaining element to end of remaining range
  for (k = size; k > 1; --k)
    g_pop_heap(beg, beg + k);
}

• in place
• not stable
• run time = Θ(n log n)
• requires random access iterators