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

        # build a heap
        hashmap = defaultdict(int)
        maxheap = []
        for num in nums:
            hashmap[num] += 1

        for num, count in hashmap.items():
            heapq.heappush(maxheap, (-count, num))

        result = []
        for _ in range(k):
            if maxheap:
                top, val = heapq.heappop(maxheap)
                result.append(val)

        return result