from typing import List
from collections import defaultdict

class Solution:
    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
        res = []
        count_elems = defaultdict(int)
        count_in = { i: set() for i in range(0, len(nums) + 1) }
        for i in range(0, len(nums)):
            cur_char = nums[i]
            count_elems[cur_char] += 1
            tmp_value = count_elems[cur_char]
            count_in[tmp_value].add(cur_char)
            count_in[tmp_value - 1].discard(cur_char)
        # Начинаем обход count_in с самого большого значения вхождений 
        for i in range(len(nums), 0, -1):
            # Если есть элементы - записываем их в массив res
            while len(count_in[i]) > 0:
                res.append(count_in[i].pop())
                # Уменьшаем значение k
                k -=1
                if k == 0:
                    return res
        return res
        
cl = Solution()
print(cl.topKFrequent(nums=[1,1,1,2,2,3], k = 2))
print(cl.topKFrequent(nums=[1], k = 1))
print(cl.topKFrequent(nums = [1,2,1,2,1,2,3,1,3,2], k = 2))