Python 3, Without iterating the array rounds, O(n), 99.18% faster
~~~\nclass Solution:\n    def mostVisited(self, n: int, rounds: List[int]) -> List[int]:\n        res = []\n        pre, post = 0, 0\n        if rounds[0] != 1:
~~~\nclass Solution:\n    def mostVisited(self, n: int, rounds: List[int]) -> List[int]:\n        res = []\n        pre, post = 0, 0\n        if rounds[0] != 1:\n            pre = rounds[0]\n        if (pre == 0) or (pre != 0 and rounds[-1] != n): post = rounds[-1]\n        if pre != 0:\n            if pre <= post:\n                for i in range(pre, post+1):\n                    res.append(i)\n                return res\n            for i in range(1, post+1):\n                res.append(i)\n            for i in range(pre, n+1):\n                res.append(i)\n        else:\n            for i in range(1, post+1):\n                res.append(i)\n        return res\n~~~\n\n**Complexity**\n\nTime O(N)\nSpace O(N)\n\n#Runtime: 32 ms, faster than 99.18% of Python3 online submissions for Most Visited Sector in a Circular Track.\n#Memory Usage: 14 MB, less than 87.95% of Python3 online submissions for Most Visited Sector in a Circular Track.
['Python3']