描述
Given a non-empty list of words, return the k most frequent elements.
Your answer should be sorted by frequency from highest to lowest. If two words have the same frequency, then the word with the lower alphabetical order comes first.
Example 1:
Input: ["i", "love", "leetcode", "i", "love", "coding"], k = 2
Output: ["i", "love"]
Explanation: "i" and "love" are the two most frequent words.
Note that "i" comes before "love" due to a lower alphabetical order.
Example 2:
Input: ["the", "day", "is", "sunny", "the", "the", "the", "sunny", "is", "is"], k = 4
Output: ["the", "is", "sunny", "day"]
Explanation: "the", "is", "sunny" and "day" are the four most frequent words,
with the number of occurrence being 4, 3, 2 and 1 respectively.
Note:
You may assume k is always valid, 1 ≤ k ≤ number of unique elements.
Input words contain only lowercase letters.
解析
根据题意，使用 lambda 语法根据单词的出现频率排序，如果频率相等，则根据单词字符升序排序。
解答
class Solution(object):
def topKFrequent(self, words, k):
"""
:type words: List[str]
:type k: int
:rtype: List[str]
"""
d={}
for word in words:
if word in d:
d[word] += 1
else:
d[word] = 1
res = sorted(d, key=lambda x: (-d[x], x))
return res[:k]
运行结果
Runtime: 44 ms, faster than 58.42% of Python online submissions for Top K Frequent Words.
Memory Usage: 13.7 MB, less than 24.20% of Python online submissions for Top K Frequent Words.
原题链接：leetcode.com/problems/to…
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