static int absShortMax(short[] l) {
  int x = 0;
  if (l != null) for (short i : l) x = max(x, abs(i));
  ret x;
}

static int absShortMax(short[] l, int start, int end) {
  int x = 0;
  for (int i = start; i < end; i++)
    x = max(x, abs(l[i]));
  ret x;
}