public static boolean intersects(@NotNull IntSet set1, @NotNull IntSet set2) {
    if (set1.size() <= set2.size()) {
      IntIterator it = set1.intIterator();
      while (it.hasNext()) {
        int value = it.nextInt();
        if (set2.contains(value)) return true;
      }
      return false;
    }
    return intersects(set2, set1);
  }
public static boolean intersects(@NotNull IntSet set1, @NotNull IntSet set2)