擅长:python、mysql、java
<p>如果<code>isUnivalTree</code>返回bool(由于名称的原因,应该返回bool):</p>
<pre><code>left_count = self.left and self.left.isUnivalTree()
</code></pre>
<p>否则:</p>
<pre><code>left_count = self.left.isUnivalTree() if self.left else None
</code></pre>