Python3 | (one line ) simple and fastest | using str, int and line comprehension
\nclass Solution:\n    def plusOne(self, digits: List[int]) -> List[int]:\n        a=[str(i) for i in digits]\n        a=\'\'.join(a)\n        a=str(int(a)+1)\n
```\nclass Solution:\n    def plusOne(self, digits: List[int]) -> List[int]:\n        a=[str(i) for i in digits]\n        a=\'\'.join(a)\n        a=str(int(a)+1)\n        return [int(i) for i in a]\n\n```\n\n**compressed into one line**\n```\nclass Solution:\n    def plusOne(self, digits: List[int]) -> List[int]:\n        return [int(i) for i in str(int(\'\'.join([str(i) for i in digits]))+1)]\n\n```
['Python', 'Python3']