R4-排序篇

class Solution:
    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
        #使用哈希表记录值，再sort
        dict=defaultdict(int)
        ret=[]
        for num in nums:
            dict[num]+=1
        the=sorted(dict.keys(),key=lambda x:dict[x], reverse=True)
        for i in range(k):
            ret.append(the[i])
        return ret