https://uphie.studio/posts/%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91%E5%9F%BA%E6%9C%AC%E6%93%8D%E4%BD%9C/
二叉搜索树基本操作 - Uphie's Blog