message: Add alternative solution for 'Array Partition' problem
diff: @@ -42,3 +42,13 @@ class Solution2(object):
  for i in xrange(0, len(nums), 2):
  result += nums[i]
  return result
  +
  +
  +class Solution3(object):
  + def arrayPairSum(self, nums):
  + """
  + :type nums: List[int]
  + :rtype: int
  + """
  + nums = sorted(nums)
  + return sum([nums[i] for i in range(0, len(nums), 2)])
  