Python solution, Simple
\n\n    def plusOne(self, digits):\n        for i in xrange(len(digits)-1, -1, -1):\n            if digits[i] < 9:\n                digits[i] += 1\n            
\n\n    def plusOne(self, digits):\n        for i in xrange(len(digits)-1, -1, -1):\n            if digits[i] < 9:\n                digits[i] += 1\n                return digits\n            digits[i] = 0\n        return [1] + digits
['Python']