参考代码:

class Solution:
    def topKFrequentWords(self, words, k):
        dict = {}
        res = []
        for word in words:
            if word not in dict:
                dict[word] = 1
            else:
                dict[word] += 1
        sorted_d = sorted(dict.items(), key = lambda x:x[1], reverse=True)
        for i in range(k):
            res.append(sorted_d[i][0])
        return res