message: update candy.py
  make it a bit more pythonic.
diff: # Time: O(n)
  # Space: O(n)
  -import operator
  -from functools import reduce
  -
  class Solution(object):
  # @param ratings, a list of integer
  # @return an integer
  @@ -17,5 +14,4 @@ class Solution(object):
  if ratings[i - 1] > ratings[i] and candies[i - 1] <= candies[i]:
  candies[i - 1] = candies[i] + 1
  - return reduce(operator.add, candies)
  -
  + return sum(candies)
  