def reverse_string_iterative(s):
	"""
	Returns the reverse of the input string

	Time complexity: O(n)

	Space complexity: O(n)

	More efficient, only 3 O(n) operations
	"""

	chars = list(s) # O(n)
	i, j = 0, len(s) - 1
	while i < j: # O(n)
		chars[i], chars[j] = chars[j], chars[i]
		i += 1
		j -= 1
	return "".join(chars)