Top k frequent elements

class Solution:
    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
        count = {}
        for num in nums:
            count[num] = count.get(num, 0) + 1
        heap = []
        for key, val in count.items():
            heapq.heappush(heap, (val, key))
            if len(heap) > k:
                heapq.heappop(heap)
        res = []
        for i in range(len(heap)):
            res.append(heapq.heappop(heap)[1])
        return res[::-1]

Top K Frequent Elements

Difficulty: Medium


Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.

 

Example 1:

Input: nums = [1,1,1,2,2,3], k = 2
Output: [1,2]

Example 2:

Input: nums = [1], k = 1
Output: [1]

 

Constraints:

  • 1 <= nums.length <= 105
  • -104 <= nums[i] <= 104
  • k is in the range [1, the number of unique elements in the array].
  • It is guaranteed that the answer is unique.

 

Follow up: Your algorithm's time complexity must be better than O(n log n), where n is the array's size.