상위 K 빈도 요소

https://leetcode.com/problems/top-k-frequent-elements/
가장 빈번한 k개의 요소를 반환하라.

from collections import defaultdict
class Solution:
    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
        numList = collections.defaultdict(int)
        answer = []
        for num in nums:
            numList[num] +=1
        numList = sorted(numList.items(), key=operator.itemgetter(1), reverse=True)
        return [numList[n][0] for n in range(k)]