static int indexOfSubListIC(L<S> x, L<S> y) {
  ret indexOfSubListIC(x, y, 0);
}

static int indexOfSubListIC(L<S> x, L<S> y, int i) {
  outer: for (; i+l(y) <= l(x); i++) {
    for (int j = 0; j < l(y); j++)
      if (neqic(x.get(i+j), y.get(j)))
        continue outer;
    ret i;
  }
  ret -1;
}