new_contents: """Leetcode 347. Top K Frequent Elements
  Medium
  
  Given a non-empty array of integers, return the k most frequent elements.
  
  Example 1:
  Input: nums = [1,1,1,2,2,3], k = 2
  Output: [1,2]
  
  Example 2:
  Input: nums = [1], k = 1
  Output: [1]
  
  Note:
  You may assume k is always valid, 1 ≤ k ≤ number of unique elements.
  Your algorithm's time complexity must be better than O(n log n), 
  where n is the array's size.
  """
  
  class Solution(object):
      def topKFrequent(self, nums, k):
          """
          :type nums: List[int]
          :type k: int
          :rtype: List[int]
          """
          pass
  
  
  def main():
      pass
  
  
  if __name__ == '__main__':
      main()
  
subject: Add lc347_top_k_frequent_elements.py