def topKFrequent(nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: List[int]
        """
        frequency = {}
        elements = []
        for x in nums:
                if x not in frequency:
                        frequency[x] = 1
                else:
                        frequency[x] += 1
        for i in range(k):
                maxKey = max(frequency, key=frequency.get)
                elements.append(maxKey)
                del frequency[maxKey]
        return elements


print(topKFrequent([1,1,1,2,2,3], 2))