message: Update greatest-common-divisor-of-strings.py
diff: @@ -16,7 +16,7 @@ class Solution(object):
  i = (i+1)%len(common)
  return True
  - def gcd(a, b): # Time: O((logn)^2)
  + def gcd(a, b): # Time: O(log(min(a, b)))
  while b:
  a, b = b, a % b
  return a
  