构建堆等高级数据结构时，底层的数组使用resize()实现动态数组

    private void resize(int newCapacity){
        E[] newData = (E[])new Comparable[newCapacity];
        for(int i = 1; i < size+1; i ++)
            newData[i] = data[i];
        data = newData;
        capacity = newCapacity;
    }