text: def solution(A, target):                                            # O(N)
      """
      Write a function that will return the indexes to be used to add up numbers
      to reach a given target.
  
      >>> solution([1, 2, 3, 4, 5], 5)
      [1, 2]
      >>> solution([5, 3, 2], 6)
      []
      """
      remaining = {}                                                  # O(1)
  
      for count, value in enumerate(A):                               # O(N)
          if value in remaining:                                      # O(1)
              return [remaining[value], count]                        # O(1)
          remaining[target - value] = count                           # O(1)
  
      return []                                                       # O(1)
  
  if __name__ == '__main__':
      import doctest
      doctest.testmod()
  