Skip to content

347. Top K Frequent Elements

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.

Solution

class Solution:
    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
        counts = {}
        for n in nums:
            counts[n] = counts.get(n, 0) + 1

        return sorted(counts.keys(), key=counts.get)[-k:]