動機

直接sort就好

Problem

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 = 2Output: [1,2]

Example 2:

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

 

Constraints:

  • 1 <= nums.length <= 105
  • 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.

Sol

sort就是O(nlog(n))，也不必要用heap，因為不用一直塞資料到heap中，所以直接sort就好

class Solution:
    def topKFrequent(self, nums: List[int], b: int) -> List[int]:
        tmp = sorted([(k,v) for (k,v) in Counter(nums).items()], key=lambda x: x[1], reverse=True)
        return [k for (k,v) in tmp[:b]]