input: Write a function to improve the time complexity of the following Python program that finds the maximum sum of any two distinct elements in the array. The function should return the maximum sum.
  
  def find_max_sum(arr):
      max_sum = 0
      left = 0
      right = len(arr) - 1
      while left < right:
          if arr[left] + arr[right] > max_sum:
              max_sum = arr[left] + arr[right]
          if arr[left] > arr[right]:
              right -= 1
          else:
              left += 1
      return max_sum
  
  assert find_max_sum([1, 2, 3, 4, 5])==9
  assert find_max_sum([10, 20, 30])==50
  assert find_max_sum([4, 7, 5, 6, 3])==13
  assert find_max_sum([1, 1, 1, 1])==2
  assert find_max_sum([])==0
output: def find_max_sum(arr):
      if len(arr) < 2:
          return 0
      first_max = max(arr)
      arr.remove(first_max)
      second_max = max(arr)
      return first_max + second_max