if (leftChildIndex < 0) {
        return -1;
      }
      return findMin(getLeftChildIndex(leftChildIndex), 4);
    }

    /**
     * Moves an element one level up from a min level to a max level (or vice versa). Returns the
     * new position of the element.
     */
    int crossOverUp(int index, E x) {
      if (index == 0) {
        queue[0] = x;
        return 0;
      }