擅长:python、mysql、java
<p>我通常使用<a href="https://docs.python.org/2/library/collections.html#collections.defaultdict" rel="nofollow"><strong>^{<cd1>}</strong></a>:</p>
<pre><code>from collections import defaultdict
def Tree():
return defaultdict(Tree)
</code></pre>
<p>用法:</p>
^{pr2}$
<p>奖励:卡拉斯唱歌<a href="https://www.youtube.com/watch?v=jcb6XxvEogs" rel="nofollow">O Mio Babbino Caro</a></p>