692. Top K Frequent Words
Đề Bài
Given an array of strings words and an integer k, return the k most frequent strings.
Return the answer sorted by the frequency from highest to lowest. Sort the words with the same frequency by their lexicographical order.
Example 1:
Input: words = ["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: words = ["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.
Constraints:
1 <= words.length <= 5001 <= words[i].length <= 10words[i]consists of lowercase English letters.kis in the range[1, The number of unique words[i]]
Follow-up: Could you solve it in O(n log(k)) time and O(n) extra space?
Thuật Toán & Kỹ Thuật
⏱️ Thời gian
O(n log n)
💾 Không gian
O(n)
Lời Giải
Python
0692-top-k-frequent-words.py
class Solution:
def topKFrequent(self, words: List[str], k: int) -> List[str]:
cnt = Counter(words)
words = list(set(words))
sortWords = sorted(words, key = lambda val: (-cnt[val], val))
return sortWords[:k]