code: private void up(int element) {
      int epos = this.pos.get(element);
      while (epos > 0) {
        int ppos = parent(epos);
        int p = this.heap.get(ppos);
        if (!this.less(p, element))
          break;
        this.heap.set(epos, p);
        this.heap.set(ppos, element);
        this.pos.set(p, epos);
        epos = ppos;
      }
      this.pos.set(element, epos);
    }
docs: Bubbles a given element up.
  @param element the element