解法： 字典统计排序

class Solution:
    def topKFrequent(self, nums: List[int], k: int) -> List[int]:

        cont = {}

        for eve in nums:
            if eve not in cont:  cont[eve] = 1
            else: cont[eve] += 1
        
        contlist = sorted(cont.items(), key=lambda x: x[1])
        res = [eve[0] for eve in contlist]
        return res[-k:]