LeetCode: 347. Top K Frequent Elements

빈도를 기억하기 위한 hashmap을 사용하자.

from collections import defaultdict
class Solution:
    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
        dic = defaultdict(int)
        for num in nums:
            dic[num] += 1
        temp = []
        for key, val in dic.items():
            temp.append([val, key])
        temp.sort(key=lambda x: -x[0])
        temp = temp[:k]
        return [t[1] for t in temp]