Given an integer array nums and an integer k, return the k most frequent elements.
The answer can be returned in any order.
Examples
Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2]
Input: nums = [1], k = 1 Output: [1]
Constraints
- 1 <= nums.length <= 100,000
- -10,000 <= nums[i] <= 10,000
- k is in the range [1, number of unique elements].