[Python3] linear search
Please pull this commit for solutions of biweekly 91. \n\n\nclass Solution:\n    def splitMessage(self, message: str, limit: int) -> List[str]:\n        prefix 
Please pull this [commit](https://github.com/gaosanyong/leetcode/commit/e8b87d04cc192c5227286692921910fe93fee05d) for solutions of biweekly 91. \n\n```\nclass Solution:\n    def splitMessage(self, message: str, limit: int) -> List[str]:\n        prefix = b = 0 \n        while 3 + len(str(b))*2 < limit and len(message) + prefix + (3+len(str(b)))*b > limit * b: \n            b += 1\n            prefix += len(str(b))\n        ans = []\n        if 3 + len(str(b))*2 < limit: \n            i = 0 \n            for a in range(1, b+1): \n                step = limit - (len(str(a)) + len(str(b)) + 3)\n                ans.append(f"{message[i:i+step]}<{a}/{b}>")\n                i += step \n        return ans \n```
['Python3']