input: Write a function to reduce the time complexity of the given Python program that finds the maximum sum of any two elements in an array.
  
  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, 40]) == 70
  assert find_max_sum([5, -2, 7, 3]) == 12
  assert find_max_sum([1]) == 0
  assert find_max_sum([]) == 0
output: def find_max_sum(arr):
      if len(arr) < 2:
          return 0
      max1 = max(arr[0], arr[1])
      max2 = min(arr[0], arr[1])
      for num in arr[2:]:
          if num > max1:
              max2 = max1
              max1 = num
          elif num > max2:
              max2 = num
      return max1 + max2