擅长:python、mysql、java
<p>您只需要构建一个“反向”树:</p>
<pre><code>from collections import defaultdict
fruits_by_vitamin = defaultdict(list) # if a key doesn't exist, set it to an
# empty list
for fruit,data in fruits.items(): # on Python2, use iteritems()
fruits_by_vitamin[data['Vitamin']].append(fruit)
print(fruits_by_vitamin['C'])
</code></pre>