text: #!/usr/bin/python3
  # -*- coding: utf-8 -*-
  # Created by Ross on 19-1-25
  
  
  def solve(array: list, win_size):
      if not array or win_size > len(array) or win_size <= 0:
          return None
      length = len(array)
      cur_sum = max_sum = sum(array[:win_size])
      win_start = 0
      left = 1
      right = win_size
      while right < length:
          cur_sum -= array[left - 1]
          cur_sum += array[right]
          if cur_sum > max_sum:
              max_sum = cur_sum
              win_start = left
          left += 1
          right += 1
      return array[win_start:win_start + win_size]
  
  
  if __name__ == '__main__':
      print(solve([2, 3, 4, 2, 6, 2, 5, 1], 3))
      print(solve([2, 6], 3))
      print(solve([2, 6, 3], 3))
      print(solve([2, 6, 3], 1))
      print(solve([2], 1))
  